if (!valid) throw new IllegalStateException("Memory region invalidated");
        return buffer;
    }
    
    public int getLocalKey() { return localKey; }
    public int getRemoteKey() { return remoteKey; }
    public long getAddress() { return address; }
    public int getSize() { return buffer.remaining(); }
    
    public boolean hasAccess(RdmaAccess access) {