// Unoptimized
// this performs a synchronized lookup for every increment
taskLoop {
    String suffix = returnCounterType();
    Stats.incr("metric_name" + suffix);
}

// Optimized
// ThreadLocalStats does not have any locks.
ThreadLocalStats tls = Stats.makeThreadLocalStats();
taskLoop {
    String suffix = returnCounterType();
    // regular lookup, not synchronized
    ThreadLocalCounter tlc = tls.counter("metric_name" + suffix);
    tlc.incr();
}
// User must flush the batch of stats at the end.
tls.flush();