After QUIT is totally random on timings, screw it.

Now uses ChannelMessageQueue.Completion.IsCompleted and should be consistent. Because _completion on UnboundedChannel respect no-synchronous-continuations, the old way doesn't behave as expected (IsCompleted isn't instantly set).

# Conflicts:
#	StackExchange.Redis/StackExchange/Redis/Interfaces/IServer.cs
#	StackExchange.Redis/StackExchange/Redis/RedisServer.cs

you know what? to hell with it: no connect logging *anywhere* unless you ask for it - it is *just noise*

* 新加scan,sentinels命令

* add command sentinels

transactions: don't log the connect crap; use a StringBuilder to buffer the tran log to avoid lots of sync blocks

Need to adjust simulated failure expectations here

Revert "show the result value in MessageFaulted, even if that means hydrating a RawResult to string"

This reverts commit d27aaa44.

This reverts commit 6ed17a99.

fix the thread-race around conditions/pending-work in RedisTransaction; this is *not* the problem we're looking for, it just needs fixing

* Add UNLINK as .KeyUnlink()

Submitting as a PR so test as reuable, but maybe we want this as an overload via some enum on .KeyDelete() instead? I'm good either way, but getting the ball rolling on #909 here.

* Add feature check for UNLINK

Ah right, 4.0.0+ only...

* Move UNLINK behind KeyDelete() and always call it if available

We still weren't testing Delete(Async)() in general, so tests added there. I've confirmed this is running DEL against 3.x and UNLINK against 5.x.

* Move GetDeleteCommand after the methods (consistent with rest of the file)

Not 100% sure this is what we figured out, but good first pass at getting there if not.

* Eliminate the need for Stream magic strings & added additional XGROUP subcommands.

- Replaced the need for magic strings with Range, ReadOffset, and GroupReadOffset structs.
- Condensed some of the method signatures due to the new structs.
- Added methods & tests for two of the XGROUP subcommands (DESTROY & DELCONSUMER).

* Updated tests with their original IDs used.

* Use a single struct to represent stream position for Group, Read, and ReadGroup commands.

- Consolidated GroupCreateOptions, GroupReadOffset, and ReadOffset into a single struct, Position.
- Removed the "Pair" structs and created StreamPosition, this will be used in the multi-stream read commands.
- Renamed RedisStreamEntry to StreamEntry.
- Also added the remaining subcommand for the XGROUP command (SETID) and an associated unit test.

* File cleanup, delete consolidated structs.

* Additional changes and unit tests for the Position struct.

* Update PositionKind enum with explicit zero value.

These need changes in assumptions to match current behaviors. We don't account for what the instant debug abort should do.