PushVideoStreamSession
class PushVideoStreamSession(val format: VideoFormat, onStop: () -> Unit = {}, bufferCapacity: Int = 128) : VideoStreamSession
A VideoStreamSession whose frames are pushed by a platform transport.
The backing queue keeps low-latency drop-oldest semantics and records real drops. Unlike kotlinx.coroutines.channels.BufferOverflow.DROP_OLDEST, this implementation increments droppedFrameCount only when it evicts an old frame to make room for the newest one.