diff --git a/src/SignalR/Directory.Build.props b/src/SignalR/Directory.Build.props
index 6269827f53..27a3751cd8 100644
--- a/src/SignalR/Directory.Build.props
+++ b/src/SignalR/Directory.Build.props
@@ -6,6 +6,11 @@
     <SignalRTestUtilsProject>$(MSBuildThisFileDirectory)common\testassets\Tests.Utils\Microsoft.AspNetCore.SignalR.Tests.Utils.csproj</SignalRTestUtilsProject>
   </PropertyGroup>
 
+  <!-- Keys used by InternalsVisibleTo attributes. -->
+  <PropertyGroup>
+    <MoqPublicKey>0024000004800000940000000602000000240000525341310004000001000100c547cac37abd99c8db225ef2f6c8a3602f3b3606cc9891605d02baa56104f4cfc0734aa39b93bf7852f7d9266654753cc297e7d2edfe0bac1cdcf9f717241550e0a7b191195b7667bb4f64bcb8e2121380fd1d9d46ad2d92d2d15605093924cceaf74c4861eff62abf69b9291ed0a340e113be11e6a7d3113e92484cf7045cc7</MoqPublicKey>
+  </PropertyGroup>
+
   <PropertyGroup Condition="'$(IsTestProject)' != 'true'">
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
diff --git a/src/SignalR/clients/csharp/Client.Core/src/Microsoft.AspNetCore.SignalR.Client.Core.csproj b/src/SignalR/clients/csharp/Client.Core/src/Microsoft.AspNetCore.SignalR.Client.Core.csproj
index 2c0e6d3609..0bc1fe9403 100644
--- a/src/SignalR/clients/csharp/Client.Core/src/Microsoft.AspNetCore.SignalR.Client.Core.csproj
+++ b/src/SignalR/clients/csharp/Client.Core/src/Microsoft.AspNetCore.SignalR.Client.Core.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>Client for ASP.NET Core SignalR</Description>
@@ -37,4 +37,9 @@
     <SuppressBaselineReference Include="Microsoft.AspNetCore.SignalR.Protocols.Json" />
   </ItemGroup>
 
+  <ItemGroup>
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Client.FunctionalTests" />
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Client.Tests" />
+  </ItemGroup>
+
 </Project>
diff --git a/src/SignalR/clients/csharp/Client.Core/src/Properties/AssemblyInfo.cs b/src/SignalR/clients/csharp/Client.Core/src/Properties/AssemblyInfo.cs
deleted file mode 100644
index 8376590f76..0000000000
--- a/src/SignalR/clients/csharp/Client.Core/src/Properties/AssemblyInfo.cs
+++ /dev/null
@@ -1,7 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System.Runtime.CompilerServices;
-
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Client.FunctionalTests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Client.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
diff --git a/src/SignalR/clients/csharp/Http.Connections.Client/src/Microsoft.AspNetCore.Http.Connections.Client.csproj b/src/SignalR/clients/csharp/Http.Connections.Client/src/Microsoft.AspNetCore.Http.Connections.Client.csproj
index 846dbfa8a7..f804da1a26 100644
--- a/src/SignalR/clients/csharp/Http.Connections.Client/src/Microsoft.AspNetCore.Http.Connections.Client.csproj
+++ b/src/SignalR/clients/csharp/Http.Connections.Client/src/Microsoft.AspNetCore.Http.Connections.Client.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>Client for ASP.NET Core Connection Handlers</Description>
@@ -19,4 +19,11 @@
     <Reference Include="Microsoft.Extensions.Logging.Abstractions" />
   </ItemGroup>
 
+  <ItemGroup>
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Microbenchmarks" />
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Tests" />
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Client.Tests" />
+    <InternalsVisibleTo Include="DynamicProxyGenAssembly2" Key="$(MoqPublicKey)" />
+  </ItemGroup>
+
 </Project>
diff --git a/src/SignalR/clients/csharp/Http.Connections.Client/src/Properties/AssemblyInfo.cs b/src/SignalR/clients/csharp/Http.Connections.Client/src/Properties/AssemblyInfo.cs
deleted file mode 100644
index 08686a03d4..0000000000
--- a/src/SignalR/clients/csharp/Http.Connections.Client/src/Properties/AssemblyInfo.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System.Runtime.CompilerServices;
-
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Client.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Microbenchmarks, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
-[assembly: InternalsVisibleTo("DynamicProxyGenAssembly2, PublicKey=0024000004800000940000000602000000240000525341310004000001000100c547cac37abd99c8db225ef2f6c8a3602f3b3606cc9891605d02baa56104f4cfc0734aa39b93bf7852f7d9266654753cc297e7d2edfe0bac1cdcf9f717241550e0a7b191195b7667bb4f64bcb8e2121380fd1d9d46ad2d92d2d15605093924cceaf74c4861eff62abf69b9291ed0a340e113be11e6a7d3113e92484cf7045cc7")]
diff --git a/src/SignalR/common/Http.Connections/ref/Microsoft.AspNetCore.Http.Connections.netcoreapp3.0.cs b/src/SignalR/common/Http.Connections/ref/Microsoft.AspNetCore.Http.Connections.netcoreapp3.0.cs
index 978e249509..64b628f6a4 100644
--- a/src/SignalR/common/Http.Connections/ref/Microsoft.AspNetCore.Http.Connections.netcoreapp3.0.cs
+++ b/src/SignalR/common/Http.Connections/ref/Microsoft.AspNetCore.Http.Connections.netcoreapp3.0.cs
@@ -61,11 +61,6 @@ namespace Microsoft.AspNetCore.Http.Connections
     {
         public NegotiateMetadata() { }
     }
-    public static partial class ServerSentEventsMessageFormatter
-    {
-        [System.Diagnostics.DebuggerStepThroughAttribute]
-        public static System.Threading.Tasks.Task WriteMessageAsync(System.Buffers.ReadOnlySequence<byte> payload, System.IO.Stream output) { throw null; }
-    }
     public partial class WebSocketOptions
     {
         public WebSocketOptions() { }
diff --git a/src/SignalR/common/Http.Connections/src/Microsoft.AspNetCore.Http.Connections.csproj b/src/SignalR/common/Http.Connections/src/Microsoft.AspNetCore.Http.Connections.csproj
index 175167df71..1504fac39f 100644
--- a/src/SignalR/common/Http.Connections/src/Microsoft.AspNetCore.Http.Connections.csproj
+++ b/src/SignalR/common/Http.Connections/src/Microsoft.AspNetCore.Http.Connections.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>Components for providing real-time bi-directional communication across the Web.</Description>
@@ -34,4 +34,8 @@
     <Reference Include="System.Security.Principal.Windows" />
   </ItemGroup>
 
+  <ItemGroup> 
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.Http.Connections.Tests" /> 
+  </ItemGroup> 
+
 </Project>
diff --git a/src/SignalR/common/Http.Connections/src/Properties/AssemblyInfo.cs b/src/SignalR/common/Http.Connections/src/Properties/AssemblyInfo.cs
deleted file mode 100644
index b849e763b6..0000000000
--- a/src/SignalR/common/Http.Connections/src/Properties/AssemblyInfo.cs
+++ /dev/null
@@ -1,6 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System.Runtime.CompilerServices;
-
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.Http.Connections.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
diff --git a/src/SignalR/common/Http.Connections/src/ServerSentEventsMessageFormatter.cs b/src/SignalR/common/Http.Connections/src/ServerSentEventsMessageFormatter.cs
index 2f69e62aa6..efd2e24f0f 100644
--- a/src/SignalR/common/Http.Connections/src/ServerSentEventsMessageFormatter.cs
+++ b/src/SignalR/common/Http.Connections/src/ServerSentEventsMessageFormatter.cs
@@ -8,7 +8,7 @@ using System.Threading.Tasks;
 
 namespace Microsoft.AspNetCore.Http.Connections
 {
-    public static class ServerSentEventsMessageFormatter
+    internal static class ServerSentEventsMessageFormatter
     {
         private static readonly byte[] DataPrefix = { (byte)'d', (byte)'a', (byte)'t', (byte)'a', (byte)':', (byte)' ' };
         private static readonly byte[] Newline = { (byte)'\r', (byte)'\n' };
diff --git a/src/SignalR/common/SignalR.Common/src/Microsoft.AspNetCore.SignalR.Common.csproj b/src/SignalR/common/SignalR.Common/src/Microsoft.AspNetCore.SignalR.Common.csproj
index d1ba59a3eb..118f42dc23 100644
--- a/src/SignalR/common/SignalR.Common/src/Microsoft.AspNetCore.SignalR.Common.csproj
+++ b/src/SignalR/common/SignalR.Common/src/Microsoft.AspNetCore.SignalR.Common.csproj
@@ -36,4 +36,9 @@
     <SuppressBaselineReference Include="System.Buffers" />
   </ItemGroup>
 
+  <ItemGroup>
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Common.Tests" />
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Tests.Utils" />
+  </ItemGroup>
+
 </Project>
diff --git a/src/SignalR/common/SignalR.Common/src/Properties/AssemblyInfo.cs b/src/SignalR/common/SignalR.Common/src/Properties/AssemblyInfo.cs
deleted file mode 100644
index 0758e9ccfc..0000000000
--- a/src/SignalR/common/SignalR.Common/src/Properties/AssemblyInfo.cs
+++ /dev/null
@@ -1,7 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System.Runtime.CompilerServices;
-
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Common.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Tests.Utils, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
diff --git a/src/SignalR/perf/Microbenchmarks/Microsoft.AspNetCore.SignalR.Microbenchmarks.csproj b/src/SignalR/perf/Microbenchmarks/Microsoft.AspNetCore.SignalR.Microbenchmarks.csproj
index 8011d5de2b..c007a68669 100644
--- a/src/SignalR/perf/Microbenchmarks/Microsoft.AspNetCore.SignalR.Microbenchmarks.csproj
+++ b/src/SignalR/perf/Microbenchmarks/Microsoft.AspNetCore.SignalR.Microbenchmarks.csproj
@@ -10,6 +10,7 @@
     <Compile Include="$(SignalRSharedSourceRoot)BinaryMessageParser.cs" Link="BinaryMessageParser.cs" />
     <Compile Include="$(SignalRSharedSourceRoot)TextMessageFormatter.cs" Link="Internal\TextMessageFormatter.cs" />
     <Compile Include="$(SignalRSharedSourceRoot)TextMessageParser.cs" Link="Internal\TextMessageParser.cs" />
+    <Compile Include="..\..\common\Http.Connections\src\ServerSentEventsMessageFormatter.cs" Link="ServerSentEventsMessageFormatter.cs" />
     <Compile Include="$(SharedSourceRoot)Buffers.Testing\**\*.cs" />
   </ItemGroup>
 
diff --git a/src/SignalR/server/Core/src/Microsoft.AspNetCore.SignalR.Core.csproj b/src/SignalR/server/Core/src/Microsoft.AspNetCore.SignalR.Core.csproj
index eeb0e55e0e..e0c5505ef0 100644
--- a/src/SignalR/server/Core/src/Microsoft.AspNetCore.SignalR.Core.csproj
+++ b/src/SignalR/server/Core/src/Microsoft.AspNetCore.SignalR.Core.csproj
@@ -23,4 +23,11 @@
     <Reference Include="Microsoft.Extensions.Logging.Abstractions" />
   </ItemGroup>
 
+  <ItemGroup>
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Tests.Utils" />
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Microbenchmarks" />
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Tests" />
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.StackExchangeRedis.Tests" />
+  </ItemGroup>
+
 </Project>
diff --git a/src/SignalR/server/Core/src/Properties/AssemblyInfo.cs b/src/SignalR/server/Core/src/Properties/AssemblyInfo.cs
deleted file mode 100644
index 95d162c8ce..0000000000
--- a/src/SignalR/server/Core/src/Properties/AssemblyInfo.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System.Runtime.CompilerServices;
-
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Tests.Utils, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Microbenchmarks, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.StackExchangeRedis.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
diff --git a/src/SignalR/server/StackExchangeRedis/src/AssemblyInfo.cs b/src/SignalR/server/StackExchangeRedis/src/AssemblyInfo.cs
deleted file mode 100644
index 84cff67885..0000000000
--- a/src/SignalR/server/StackExchangeRedis/src/AssemblyInfo.cs
+++ /dev/null
@@ -1,7 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System.Runtime.CompilerServices;
-
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.StackExchangeRedis.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
-[assembly: InternalsVisibleTo("Microsoft.AspNetCore.SignalR.Microbenchmarks, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
diff --git a/src/SignalR/server/StackExchangeRedis/src/Microsoft.AspNetCore.SignalR.StackExchangeRedis.csproj b/src/SignalR/server/StackExchangeRedis/src/Microsoft.AspNetCore.SignalR.StackExchangeRedis.csproj
index c90014cd85..21e567d8a6 100644
--- a/src/SignalR/server/StackExchangeRedis/src/Microsoft.AspNetCore.SignalR.StackExchangeRedis.csproj
+++ b/src/SignalR/server/StackExchangeRedis/src/Microsoft.AspNetCore.SignalR.StackExchangeRedis.csproj
@@ -18,4 +18,9 @@
     <Reference Include="Microsoft.AspNetCore.SignalR.Core" />
   </ItemGroup>
 
+  <ItemGroup>
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.StackExchangeRedis.Tests" />
+    <InternalsVisibleTo Include="Microsoft.AspNetCore.SignalR.Microbenchmarks" />
+  </ItemGroup>
+
 </Project>