java driver (v3.x) throttling for async execution

throttle.java

private boolean availableInFlightSlots(Statement st) {
    boolean available = false;
    Iterator<Host> hostIterator = loadBalancingPolicy.newQueryPlan(session.getLoggedKeyspace(), st);
    hostIter: while(hostIterator.hasNext()) {
        Host host = hostIterator.next();
        int inFlightQueries = session.getState().getInFlightQueries(host);
        switch(loadBalancingPolicy.distance(host)) {
            case LOCAL:
                if (inFlightQueries < maxInFlightLocal) {
                    available = true;
                    break hostIter;
                }
                break;
            case REMOTE:
                if (inFlightQueries < maxInFlightRemote) {
                    available = true;
                    break hostIter;
                }
                break;
            default:
                // IGNORED is something we're not going to write to
                break;
        }
    }
    return available;
}

private ResultSetFuture scheduleStatement(Statement st, Scheduler scheduler) {
    while(true) {
        if(availableInFlightSlots(st)) {
            return session.executeAsync(st);
        } else {
            try {
                Thread.sleep(0, 1);
            } catch (InterruptedException e) {
                    //
        }
    }
}

public ResultSetFuture execute(Statement query) {
    return scheduleStatement(query));
}