send bitrate limit

[xiaoshuyu6]

Hello！ When I rerun RTP-over-QUIC for data transmission, both using Scream and other methods, I consistently encounter an issue where the actual maximum bitrate transmitted remains below 1.2 Mbps. Despite my attempts to modify the configuration by examining the code, I have been unable to resolve this limitation. I would appreciate it if the author could provide guidance on how to successfully achieve a higher bitrate during testing.