Links may queue deliveries for a number of reasons, for example there may be insufficient
{@link #getCredit() credit} to send them to the receiver, they may not have yet had a chance
to be written to the wire, or the receiving application has simply not yet processed them.
Gets the number of queued messages for a link.
Links may queue deliveries for a number of reasons, for example there may be insufficient {@link #getCredit() credit} to send them to the receiver, they may not have yet had a chance to be written to the wire, or the receiving application has simply not yet processed them.
@return the queued message count for the link