A single message posted to an in-memory MockQueue.
Create a new message. Use {MockQueue#add_message} instead.
Determine how long ago this message was created, in seconds.
@return [Integer]
Return true if this message has been claimed.
@return [Boolean]
Determine if this message has lived longer than its designated ttl.
Extend the {ttl} of this message to include the lifetime of the claim it belongs to, plus the claim‘s grace period.
Generate a URI segment that identifies this message.
@return [String]
Convert this message to a GET payload.
@return [Hash]
[Validate]