Feature Request: Support --speed flag in ffmpeg_kit_flutter

[zamaniafshar]

I want to express my appreciation for the excellent tool you've created. It's incredibly helpful. However, one issue I've encountered is its speed. I came across the Speed Optimization Page in the wiki and was eager to implement it in my Flutter project. Unfortunately, after some research, I discovered that this isn't currently possible.

Link to the issue: Issue #678

My suggestion is to consider creating another packages that's built with the --speed flag enabled. In a Flutter project's pubspec.yaml, users could then specify:

ffmpeg_kit_flutter_audio_speed: ^6.0.3

Thank you for your attention to this matter.