StreamMediaInput optimizations

Problem to solve

Improve StreamMediaInput performance.

Intended users

People who need more perf when proving their own input stream to libvlcsharp.

Proposal

• Add benchmarks like https://github.com/SixLabors/ImageSharp/blob/master/tests/ImageSharp.Benchmarks/General/IO/BufferedStreams.cs
• Add [MethodImpl(MethodImplOptions.AggressiveInlining)] in a few places, like done in https://github.com/SixLabors/ImageSharp/blob/master/src/ImageSharp/IO/BufferedReadStream.cs.
• See perf numbers after that change.

Documentation