read lines async benchmarks: how channels affect perf

[adamsitnik]

dotnet run -c Release -f net10.0 --filter *RedirectToPipe*

BenchmarkDotNet v0.15.8, Windows 11 (10.0.26200.8246/25H2/2025Update/HudsonValley2)
AMD Ryzen Threadripper PRO 3945WX 12-Cores 3.99GHz, 1 CPU, 24 logical and 12 physical cores
.NET SDK 11.0.100-preview.4.26210.111
  [Host]     : .NET 10.0.6 (10.0.6, 10.0.626.17701), X64 RyuJIT x86-64-v3
  Job-IJTVWC : .NET 10.0.6 (10.0.6, 10.0.626.17701), X64 RyuJIT x86-64-v3

Method	Mean	Ratio	Completed Work Items	Allocated	Alloc Ratio
OldSyncEvents	209.4 ms	baseline	8.0000	112.08 KB
OldReadToEndAsync	206.5 ms	1.01x faster	6.0000	89.59 KB	1.25x less
NoChannelsAsync	196.7 ms	1.06x faster	4.0000	88.95 KB	1.26x less
ChannelsAsync	201.9 ms	1.04x faster	119.0000	96.58 KB	1.16x less