I do TCP client board, to establish a TCP connection after after using tcp_write to write data into the buffer, then tcp_output function to send data, reference when atoms of procedure, send to normal at the beginning, hair hair appears tcp_write return ERR_MEM mistakes, as if every time is can't send after receive data appear this error, I found in the debug to the function is what went wrong in the picture, does anyone know what reason be? I feel is not sent successfully, and then continue to tcp_write write data buffer, the buffer is not enough, but I don't know how to get rid of the buffer data