this provides the exactly one inorder delivery
used to buffer the incomming messages so that
later it can invoke in correct order
the state of the invoker buffer is determined by the
following variables
LMR - last message received
MIB - messages in the buffer
TMR - terminate message received
these three variables forms possible 8 states
but states 001,100,101 can be considered as one
complete sate.
this handler is useful only for response messages of duplex mode in out operations
In Axis2 when it sends a message it registers the messageID with the
Operation context in the Configuration context.
each RM specific message class should extends from this class
in addition to toSOAPEnvelope those classes should have
static fromSOAPEnvelope to parse the data.