input: [Token] BDAT [Type] Verb [Reference] RFC3030 [SMTP server] Microsoft Exchange Server [Comments] 
output: Should only be used if the CHUNKING keyword is sent. Like the DATA command, but if accepted data of a length specified in BDAT follows. No need for a terminator. Can be multiple chunks - the last BDAT command comes with a LAST parameter. Cannot mix BDAT and DATA