public void grantSendCredit() {
        sendCredits.incrementAndGet();
    }
    
    public void grantReceiveCredit() {
        receiveCredits.incrementAndGet();
    }
    
    public int getAvailableSendCredits() {
        return sendCredits.get();
    }
    
    public int getAvailableReceiveCredits() {
        return receiveCredits.get();
    }
}
```

### 4.2 RDMA Memory Region
```java