Proposed resolution for Rel 50

Title: Proposed resolution for Rel 50

Rel 50: Semantics of ExpiryTime:

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Proposal:

ExpiryTime indicates the ultimate date after which the receiver RMP will

not accept a message. In order to be accepted by an RMP, a message 

must have schema-valid RM headers, and must not have expired.

Only accepted messages are subject to further processing by the RMP.

When receiving a message after its ExpiryTime date, an RMP MUST NOT accept the message.

Once a message has been accepted by the RMP, the fact that the message expires while

being processed by the RMP MUST NOT affect its processing, nor its final availability 

status to the receiver application. Such expired messages must still be delivered to

the application, assuming they satisfy other reliability requirements.

NOTE: 

Although ExpiryTime will not affect further the processing of accepted messages,

it is useful for an RMP to remember it in order to avoid unnecessary duplicate checks

with future messages, when "at most once" delivery is required. 

Given the above definition of ExpiryTime, it is impossible that a received message M

accepted by the RMP, is a duplicate of past messages that are expired at the time M 

was accepted.