Hi. I found that Unity Transport 0.3.0-p6 provides new API for sending data, NetworkDriver.BeginSend() end EndSend(), returns DataStreamWriter. The problem is that returned DataStreamWriter's capacity is fixed to MTU size, so I can't implement my own packet fragmentation pipeline. Previous version of Unity Transport allows specifying custom DataStreamWriter for Send(). For patcket fragmentation, NetworkDriver.BeginSend() should accept large size packet and it should be splitted into small packets in pipeline. Only need that final output should fit maximum capacity of network interface, not Driver's input. Thanks.