1. A method of quiescing a set of messages processed within a distributed system, the method comprising: sending, by a computer processor, a first message to each of a plurality of nodes, the first message indicating that a quiescing protocol is to begin and that the nodes should prevent any new messages that change a state of the distributed system from being created; receiving a second message from each of the plurality of nodes, each second message indicating that the node, which has sent that second message, has sent a third message to each of the plurality of nodes and that the node, which has sent that second message, has received a fourth message from each of the plurality of nodes, wherein the third message is a message requesting the fourth message, and wherein the fourth message indicates that the third message was received by the node to which it was sent and signifies that all messages that change a state of the distributed system previously sent by the node, which has sent that second message, to that node, which has sent that fourth message, have been processed; determining, by the computer processor, that second messages have been received from all of the plurality of nodes; based on the determination that second messages have been received from all of the plurality of nodes, sending, by the computer processor, a fifth message to each of the plurality of nodes, the fifth message requesting information about whether any new messages that change a state of the distributed system have been received from the plurality of nodes; receiving a sixth message in response to the fifth message from each of the plurality of nodes, the sixth message including information related to the number of new messages, if any, that change a state of the distributed system that have been received, by the node which has sent the sixth message, from the plurality of nodes; based on at least one received sixth message, determining, by the computer processor, that the distributed system has been quiesced if none of the plurality of nodes have received any new messages that change a state of the distributed system; and if any of the plurality of nodes has received new messages that change a state of the distributed system, repeating the method of this claim until it is determined, by the computer processor, that none of the plurality of nodes have received any new messages that change a state of the distributed system.