make sender balancing smater

[wsky]

#24

    protected int calculate(int pending) {
        if (!this.balancing)
            return this.maxFlushCount;
        //TODO make it smarter
        int flushCount = this.highwater / pending;
        if (flushCount > this.maxFlushCount)
            flushCount = this.maxFlushCount;
        if (flushCount < this.minFlushCount)
            flushCount = this.minFlushCount;
        return flushCount;
    }

[wsky]

• totalPending < highwater, flush all
• else, avg=highwater/clientCount
• loop clients,
• if client.pendingCount<avg, freeCount+=avg-client.pendingCount
• else clientCount2+=1
• avg2=avg1+freeCount/clientCount2