Default write buffer size can break communication with Roach2 boards.

[baileyji]

Hi Folks,
We've found that to get casperfpga working with our roach2 based system we need to add the additional patch of:

if hasattr(katcp.CallbackClient, 'MAX_WRITE_BUFFER_SIZE'):
    setattr(katcp.CallbackClient, 'MAX_WRITE_BUFFER_SIZE',
            katcp.CallbackClient.MAX_WRITE_BUFFER_SIZE * 10)

in katcp_fpga.py (v0.4.2) or probably in transport_katcp.py for v3.1 (untested). We aren't keen on this because it means forking and diving into internals.

Is there an undocumented way of perhaps calling casperfpga.katcp_fpga.KatcpFpga with a MAX_MESSAGE_LEN argument or some such so we can both avoid the write buffer overflow and mucking around with or forking the repo?