Retrieve the sequence number of a message.
Messages have ever-incrementing sequence numbers, which may also be set explicitly via set_seqnum. Sequence numbers are typically used to indicate that a message corresponds to some other set of messages or events, for example a SEGMENT_DONE message corresponding to a SEEK event. It is considered good practice to make this correspondence when possible, though it is not required.
Note that events and messages share the same sequence number incrementor; two events or messages will never have the same sequence number unless that correspondence was made explicitly.
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A Message. |