1. few more optimizations on top of ZPipeline.fromFunction benchmark and optimization #8761

initial benchmark results:

Benchmark                                     (chunkCount)  (chunkSize)   Mode  Cnt    Score   Error  Units
StreamBenchmarks.zioChunkToConstBaseline             10000         5000  thrpt   15  148.078 ± 4.111  ops/s
StreamBenchmarks.zioChunkToConstDirect               10000         5000  thrpt   15  232.269 ± 2.481  ops/s
StreamBenchmarks.zioChunkToConstFromFunction         10000         5000  thrpt   15  133.889 ± 0.352  ops/s

after applying the optimizations:

[info] Benchmark                                     (chunkCount)  (chunkSize)   Mode  Cnt    Score   Error  Units
[info] StreamBenchmarks.zioChunkToConstBaseline             10000         5000  thrpt   15  244.041 ± 1.084  ops/s
[info] StreamBenchmarks.zioChunkToConstDirect               10000         5000  thrpt   15  366.264 ± 1.715  ops/s
[info] StreamBenchmarks.zioChunkToConstFromFunction         10000         5000  thrpt   15  245.392 ± 1.611  ops/s

optimization techniques applied:

1. ChannelExecutor.readUpstream
   a. make the internal read method tail recursive
   b. instead of suspending on each recurse, count consecutive operations and suspend every N steps (currently set to 128), this is important in order to keep the stream interruptible.
   c. reduce stack mutations by separating the current Read from the rest, for some reads this means they'd never make it into the stack, for others it avoids pushing the same read immediately after popping it from the stack.
2. ChannelExecutor.execToPullingChannel, implement readUpstream as a channel. this avoids going through effects for some code paths and eliminate the need for the onSuccess and onFailure effects.
3. reorder cases in ChannelExecutor.run, make sure frequent channel constructors appear earlier in the pattern matching.