* remove the entire concept of the completion manager; it just doesn't make sense any more; everything async and external facing should be via the TP

* use "in" with ForAwait to avoid some extra copies

* experimental "backlog queue" approach

* Cleanup and de-dupe timeout exception data

* WriteMessageTakingWriteLockSync should consider backlog

* don't allocate all those strings

* this compiles, but nothing else; not tested yet

* fix the by-ref indexer

* record that CompletedSynchronously has changed - impacts a test

* update benchmarks and rev unofficial

* update to  pipelines 1.1.2 and simplify

* in debug mode, use a small page size in the arena

* rev pipelines to 1.1.3

* Update src/StackExchange.Redis/CommandTrace.cs
Co-Authored-By: mgravell <marc.gravell@gmail.com>

* Perf regression (#1076)

* compare baseline to 1.2.6

* remove the entire concept of the completion manager; it just doesn't make sense any more; everything async and external facing should be via the TP

* use "in" with ForAwait to avoid some extra copies

* experimental "backlog queue" approach

* Cleanup and de-dupe timeout exception data

* WriteMessageTakingWriteLockSync should consider backlog

* don't allocate all those strings