For a receiving Delivery, this means the delivery does not hold
a complete message payload as all the content hasn't been
received yet. Note that an {@link #isAborted() aborted} delivery
will also be considered partial and the full payload won't
be received.
For a sending Delivery, this means the sender link has not been
{@link Sender#advance() advanced} to complete the delivery yet.
@return true if the delivery is partial
@see #isAborted()
Check for whether the delivery is still partial.
For a receiving Delivery, this means the delivery does not hold a complete message payload as all the content hasn't been received yet. Note that an {@link #isAborted() aborted} delivery will also be considered partial and the full payload won't be received.
For a sending Delivery, this means the sender link has not been {@link Sender#advance() advanced} to complete the delivery yet.
@return true if the delivery is partial @see #isAborted()