Refactor Java Driver to have one method for connection selection

 if (borrowed >= maxSimultaneousUsagePerConnection && leastUsedConn.availableInProcess() == 0) {

final int inFlight = leastUsed.borrowed.get();
                    final int availableInProcess = leastUsed.availableInProcess();
                    if (inFlight >= availableInProcess) {
                        logger.debug("Least used {} on {} has requests borrowed [{}] >= availableInProcess [{}] - may timeout waiting for connection",
                                leastUsed, host, inFlight, availableInProcess);
                        break;
                    }

                    if (leastUsed.borrowed.compareAndSet(inFlight, inFlight + 1)) {
                        if (logger.isDebugEnabled())
                            logger.debug("Return least used {} on {} after waiting", leastUsed.getConnectionInfo(), host);
                        return leastUsed;
                    }