While file sizes are now properly-represented with 64-bit integers (see
GUACAMOLE-268), the offset of each read/write is still a simple int. This will limit the location of each read or write to a 32-bit addressable space, thus effectively limiting the size of files transferred to 4 GB:
It couldn't hurt to check over the rest of the RDP implementation to see where we might be reading a 64-bit value into an int. Usages of the Stream_Read_UINT64() macro which read into an int will happily truncate the result without any compiler warning due to the type cast included within the macro definition.