The second step of raw transfer is to transfer the format data itself.
This has been already implemented in XFreeRDP before, but several
tweaks are required for it to work correctly.
The idea of raw data transfer is to request for _FREERDP_RAW clipboard
format while putting the actual formatId into _FREERDP_CLIPRDR property
where the requested data is expected to arrive to. Then the clipboard
owner will check for the real formatId and deliver the expected data.
This stays true, but the check is performed in a more straightforward
way, and CF_RAW format (numerically equal to zero) is not considered
an unknown destination format when performing (identity) conversions
with wClipboard. This is not an issue because wClipboard will allow
only identity conversion for CF_RAW, it will fail if something else
is going to be converted into CF_RAW.