//if not found, assume the receiver came first, register it to the mailbox in the classical way
if (!other_synchro) {
XBT_DEBUG("We have messages in the permanent receive list, but not the one we are looking for, pushing request into fifo");
other_synchro = this_synchro;
SIMIX_mbox_push(mbox, this_synchro);
} else {
//if not found, assume the receiver came first, register it to the mailbox in the classical way
if (!other_synchro) {
XBT_DEBUG("We have messages in the permanent receive list, but not the one we are looking for, pushing request into fifo");
other_synchro = this_synchro;
SIMIX_mbox_push(mbox, this_synchro);
} else {