digraph eoe {
    node [fontname="Helvetica"]
    edge [fontname="Helvetica",fontsize=12]

    start [shape=point]
    start -> query

    query [label="Query all Mailboxes"]
    query -> check_read

    check_read [shape=diamond,label="Frames to read?"]
    check_read -> unset_idle_read [label="yes"]
    check_read -> check_idle_read [label="no"]

    unset_idle_read [label="Reset idle flag"]
    unset_idle_read -> read

    read [label="Read next segment"]
    read -> check_read_finished

    check_read_finished [shape=diamond,label="Frame complete?"]
    check_read_finished -> read [label="no"]
    check_read_finished -> check_write [label="yes"]

    check_idle_read [shape=diamond,label="Idle flag set?"]
    check_idle_read -> set_idle_read [label="no"]
    check_idle_read -> sleep_read [label="yes"]

    set_idle_read [label="Set idle flag"]
    set_idle_read -> check_write

    sleep_read [label="Sleep"]
    sleep_read -> check_write

    check_write [shape=diamond,label="Frames to write?"]
    check_write -> unset_idle_write [label="yes"]
    check_write -> check_idle_write [label="no"]

    unset_idle_write [label="Reset idle flag"]
    unset_idle_write -> write

    write [label="Write next segment"]
    write -> check_write_finished

    check_write_finished [shape=diamond,label="Frame complete?"]
    check_write_finished -> check_read_remaining [label="yes"]
    check_write_finished -> write [label="no"]

    check_read_remaining [shape=diamond,label="Remaining segments to read?"]
    check_read_remaining -> query [label="no"]
    check_read_remaining -> read [label="yes"]

    check_idle_write [shape=diamond,label="Idle flag set?"]
    check_idle_write -> set_idle_write [label="no"]
    check_idle_write -> sleep_write [label="yes"]

    set_idle_write [label="Set idle flag"]
    set_idle_write -> check_read_remaining

    sleep_write [label="Sleep"]
    sleep_write -> query

    /*{rank=same; check_read; check_idle_read}
    {rank=same; unset_idle_read; set_idle_read; sleep_read}
    {rank=same; check_write; check_idle_write}
    {rank=same; unset_idle_write; set_idle_write; sleep_write}*/
}