- #561
- new `SetCookieHeaderValue.AppendToStringBuilder()` method; avoids per-call `StringBuilder` allocation
- `ResponseCookies` uses `ObjectPool<StringBuilder>` that `ResponseCookiesFeature` provides
- `ResponseCookies` works fine if no `ObjectPoolProvider` is available
- `IHttpContextFactory` instance is a singleton instantiated from CI
- make `HttpContextFactory` `ObjectPoolProvider` and `ResponseCookiesFeature`-aware
- apply same pattern to sample `PooledHttpContextFactory`
- pool is not currently configurable; defaults are fine for response cookies
- if we need (policy) configuration, would add an `IOptions<HttpContextFactorySettings>`
nit: Add some doc comments
Chris R
Doug Bunting
Brennan
N. Taylor Mullen