@Override
    public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) {
        command = wrapper.wrap(command);
        return delegate.scheduleWithFixedDelay(command, initialDelay, delay, unit);
    }
Inheritance is not recommended.
No inheritance makes the trace more intuitive.
e.g) class TraceExecutorService extends TraceExecutor {}
agent-module/agent-sdk/src/main/java/com/navercorp/pinpoint/sdk/v1/concurrent/TraceScheduledExecutorService.java