Sessions

The following session messages are supported in both directions:

Message	Type	Comment
Logon	A	Begin session (or resume a broken session).
Heartbeat	0
Test Request	1
Resend Request	2
Reject	3	Malformed message or improper session level handling.
Sequence Reset	4	Both Gap Fill (GapFillFlag = Y) and Reset.
Logout	5	Used to gracefully close session.