Don't swallow too many exceptions

- Swallowing too many exceptions can end up hiding issues in
  Kestrel itself. It's better to let the process die.
- If we want to handle certain exceptions we should be as
  specific as possible with our try/catch blocks.

src/Microsoft.AspNet.Server.Kestrel/Http/Connection.cs

@@ -93,6 +93,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
             catch (Exception ex)
             {
                 Log.LogError("Connection._frame.Consume ", ex);
+                throw;
             }
         }
 

src/Microsoft.AspNet.Server.Kestrel/Infrastructure/KestrelThread.cs

@@ -276,6 +276,7 @@ namespace Microsoft.AspNet.Server.Kestrel
                     else
                     {
                         _log.LogError("KestrelThread.DoPostWork", ex);
+                        throw;
                     }
                 }
             }
@@ -299,6 +300,7 @@ namespace Microsoft.AspNet.Server.Kestrel
                 catch (Exception ex)
                 {
                     _log.LogError("KestrelThread.DoPostCloseHandle", ex);
+                    throw;
                 }
             }
         }

src/Microsoft.AspNet.Server.Kestrel/Networking/UvConnectRequest.cs

@@ -67,6 +67,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Networking
             catch (Exception ex)
             {
                 req._log.LogError("UvConnectRequest", ex);
+                throw;
             }
         }
     }

src/Microsoft.AspNet.Server.Kestrel/Networking/UvStreamHandle.cs

@@ -133,6 +133,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Networking
             catch (Exception ex)
             {
                 stream._log.LogError("UvConnectionCb", ex);
+                throw;
             }
         }
 
@@ -172,6 +173,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Networking
             catch (Exception ex)
             {
                 stream._log.LogError("UbReadCb", ex);
+                throw;
             }
         }
 

src/Microsoft.AspNet.Server.Kestrel/Networking/UvWriteReq.cs

@@ -167,6 +167,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Networking
             catch (Exception ex)
             {
                 req._log.LogError("UvWriteCb", ex);
+                throw;
             }
         }
     }