[Twisted-Python] Limit on transport.write

Hi, all I'm writing a program to transfer files over Internet. Sometimes the files would be very big. Therefore, I'm not sure whether I could read a large block of data and send them via one time internet.protocol.transport.write(). On the other hand, does the function internet.protocol.transport.write() have any buffer scheme? If so, I could just read one line of the file each time and call that function. Or if you have any advice on how to transfer large amount of data, please let me know. Really appreciated. Best, Hanks