This feature generates a unique ID per request. This unique ID can be
used in event source and logging.
Also, this change improves KestrelEventSource by moving it back into the
Kestrel.Core assembly and de-coupling from the Libuv transport. This
adds two new events, RequestStart and RequestStop, which can be used to
identify the correlation between connection ID and request trace
identifier.
- Changed socket output to be based on pipelines
- Changed connection filter glue to be based on pipelines
- Codegen that used `MemoryPoolIterator` for output now uses `WritableBuffer`
- Made `UvWriteReq` async/await friendly with `LibuvAwaitable<T>`
- Deleted MemoryPool and friends