# Alice and Bob: batch data sync
msc {
  hscale="2", wordwraparcs=on;

  alice [label="Alice"],
  bob [label="Bob"];

  --- [label="batch data sync"];
  alice => alice [label="add messages to payload state"];
  alice >> bob [label="send payload with messages"];

  bob => bob [label="add acks to payload state"];
  bob >> alice [label="send payload with acks"];
}