See: https://issues.apache.org/jira/browse/DISPATCH-1235

In this case the delivery may have a single peer (e.g. inbound), while that peer has multiple peers (eg. outbounds). The current code assumes symmetry (either both have multiple or both have single peers).

Can result it crash with backtrace when receiving clients unexpectedly disconnect while a large message is being multicast:

#4 0x0000000004ead2fa in qdr_deliver_continue_peers_CT (core=0x1a9c3550, in_dlv=0x1da28228) at /home/kgiusti/work/dispatch/qpid-dispatch/src/router_core/transfer.c:1217
#5 0x0000000004ead439 in qdr_deliver_continue_CT (core=0x1a9c3550, action=0x1dc4c028, discard=false)
at /home/kgiusti/work/dispatch/qpid-dispatch/src/router_core/transfer.c:1259
#6 0x0000000004ea570f in router_core_thread (arg=0x1a9c3550) at /home/kgiusti/work/dispatch/qpid-dispatch/src/router_core/router_core_thread.c:124
#7 0x000000000553b594 in start_thread () from /lib64/libpthread.so.0
#8 0x00000000062caf4f in clone () from /lib64/libc.so.6