message TimestampMessage {
    required uint64 timestamp = 1;
    required uint64 id = 2;
}

message ReadMessage {
    required string key = 1;
    required TimestampMessage readtime = 2;
}

message WriteMessage {
    required string key = 1;
    required string value = 2;
}

// A serialized transaction
message TransactionMessage {
    repeated ReadMessage readset = 1;
    repeated WriteMessage writeset = 2;
}