Counter actor (stateful)

StatefulCounterActor.fs

let counterActor (mailbox: Actor<_>) =
    let rec loop lastTime countTotal countMigrated countFailed =
        actor {
            let! event = mailbox.Receive()
            let countTotal = countTotal+1
            return!
                match event with
                | Increment.Total currentId ->
                    if countTotal % 1000 = 0 then
                        // Omitted debug print to console
                        loop DateTime.Now countTotal countMigrated countFailed
                    else
                        loop lastTime countTotal countMigrated countFailed
                | Increment.Migrated ->
                    loop lastTime countTotal (countMigrated+1) countFailed
                | Increment.Failed ->
                    loop lastTime countTotal countMigrated (countFailed+1)
        }
    loop DateTime.Now 0 0 0