不清楚,你这样试试.
var
  newCount, OldCount: Integer;
begin
  NewCount := 发送的字节数.  //得到send buffer size:
  getsockopt(ClientSocket1.Socket.Sockethandle, SOL_SOCKET, SO_SNDBUF,PChar(@OldCount),SizeOf(OldCount));  //设置新的send buffer
  setsockopt(ClientSocket1.Socket.Sockethandle, SOL_SOCKET, SO_SNDBUF,PChar(@Count),SizeOf(Count));  socketstream.write(...);
  //调置回来
  setsockopt(ClientSocket1.Socket.Sockethandle, SOL_SOCKET, SO_SNDBUF,PChar(@OldCount),SizeOf(OldCount));end;