Most of the Microsoft RDP documentation describes PDUs on-the-wire.
However, [MS-RDPESC] doesn't do this. It uses DCE IDL to describe the
contents of the PDUs sent over the File System Virtual Channel.
Ideally we'd use an IDL compiler to generate the interfaces in
[MS-RDPESC]. We don't have one though, so all PDUs are read and written
with the low-level streaming routines. It's not clear in the existing
code how IDL is mapped down to this level.
This commit updates the smartcard code with comments which will enable
maintainers to better understand the IDL-to-streaming mappings.
e138c1a601