Add SDMMD_DebuggingLogData/Send/Recv.
Add SDMMD_DebuggingSendAck/RecvAck
Not enough indirection.
Buffer is one too long.
Expect an Ack on send.
Buffer full received command. Send ACK.

I feal really bad for rewriting this.
Simplify.
Read Response after send.

If we do not do this, this clogges up the message line.
Ideally we should move to reading the whole data in and
tokenize the packages.  Parsing them subsequently!