Improve performance of NetworkSession.SendBundle

[FlaggAC]

Notably, the performance improvement is much greater when the packet back-pressure is high. This is likely due to the previous implementation of pruning items from a removal list.

The number with each benchmark is the number of messages in the bundle.

The message used for benchmarking:
new GameMessagePlayerKilled("Lorem Ipsum Lorem Ipsum Lorem Ipsum Lorem Ipsum Lorem Ipsum", new ObjectGuid(0x80000000), new ObjectGuid(0x80000001))

I would advise some kind of extensive testing before releasing. I only made sure to do a few basic functions ingame.

BenchmarkDotNet v0.13.12, Windows 11 (10.0.22631.3880/23H2/2023Update/SunValley3)
Intel Core i9-10850K CPU 3.60GHz, 1 CPU, 20 logical and 10 physical cores
.NET SDK 8.0.303
  [Host]     : .NET 8.0.7 (8.0.724.31311), X64 RyuJIT AVX2
  DefaultJob : .NET 8.0.7 (8.0.724.31311), X64 RyuJIT AVX2


| Method              | Mean            | Error         | StdDev        | Median          | Gen0    | Gen1   | Allocated |
|-------------------- |----------------:|--------------:|--------------:|----------------:|--------:|-------:|----------:|
| SendBundle_Old_1    |        62.64 ns |      1.165 ns |      1.090 ns |        62.61 ns |  0.0275 |      - |     288 B |
| SendBundle_Old_10   |     1,536.86 ns |     30.206 ns |     73.525 ns |     1,525.48 ns |  0.5379 | 0.0019 |    5632 B |
| SendBundle_Old_100  |    26,285.28 ns |    518.723 ns |  1,149.454 ns |    26,516.33 ns |  5.0659 | 0.0916 |   52992 B |
| SendBundle_Old_1000 | 1,388,448.45 ns | 26,634.106 ns | 30,671.876 ns | 1,374,837.99 ns | 48.8281 | 5.8594 |  518129 B |
| SendBundle_New_1    |        52.74 ns |      1.065 ns |      2.000 ns |        52.23 ns |  0.0268 |      - |     280 B |
| SendBundle_New_10   |     1,101.58 ns |     22.005 ns |     59.492 ns |     1,084.54 ns |  0.4654 | 0.0019 |    4880 B |
| SendBundle_New_100  |    10,116.14 ns |    191.578 ns |    255.751 ns |    10,037.81 ns |  4.4250 | 0.0610 |   46344 B |
| SendBundle_New_1000 |   101,756.68 ns |  2,029.821 ns |  3,861.946 ns |   100,630.79 ns | 43.5791 | 5.6152 |  456752 B |

[FlaggAC]

These lines were removed because they have no effect

[gmriggs]

thanks for all of these performance improvements, great stuff!