*
 * Represents a registered memory region that can be used for
 * RDMA operations. The memory region contains a buffer, access
 * permissions, and keys for local and remote access.
 */
public abstract class RdmaMemoryRegion implements AutoCloseable {

    /** Memory buffer for RDMA operations */
    protected final ByteBuffer buffer;
    /** Access permissions for this memory region */
    protected final EnumSet<RdmaAccess> accessFlags;

    public void testReleaseSendRegion() throws Exception {
        RdmaMemoryRegion region = bufferManager.getSendRegion(1024);
        assertNotNull(region);

        // Release should not throw exception
        assertDoesNotThrow(() -> bufferManager.releaseSendRegion(region));
    }

    @Test
    public void testGetReceiveRegion() throws Exception {
        RdmaMemoryRegion region = bufferManager.getReceiveRegion();

    private static final Logger log = LoggerFactory.getLogger(RdmaBufferManager.class);

    private final RdmaProvider provider;
    private final ConcurrentLinkedQueue<RdmaMemoryRegion> availableSendRegions;
    private final ConcurrentLinkedQueue<RdmaMemoryRegion> availableReceiveRegions;
    private final AtomicLong totalAllocated;
    private final AtomicLong totalReleased;

    // Buffer pool configuration

        /** RDMA read operation */
        READ,
        /** RDMA write operation */
        WRITE
    }

    private final long requestId;
    private final RequestType type;
    private final RdmaMemoryRegion memoryRegion;
    private volatile boolean completed;
    private volatile Exception error;

    /**
     * Create new RDMA work request
     *
     * @param requestId unique request identifier

import jcifs.internal.smb2.rdma.RdmaAccess;
import jcifs.internal.smb2.rdma.RdmaMemoryRegion;

/**
 * TCP memory region implementation.
 *
 * For TCP fallback, memory regions are just wrappers around
 * ByteBuffers since no real RDMA registration is needed.
 */
public class TcpMemoryRegion extends RdmaMemoryRegion {

    private static final AtomicInteger keyGenerator = new AtomicInteger(1000);

    /**

        }
    }

    @Override
    public void rdmaRead(RdmaMemoryRegion localRegion, long remoteAddress, int remoteKey, int length) throws IOException {
        // TCP fallback doesn't support real RDMA read
        throw new UnsupportedOperationException("RDMA read not supported by TCP fallback");
    }

    @Override

import org.junit.jupiter.api.Test;

import jcifs.internal.smb2.rdma.RdmaAccess;
import jcifs.internal.smb2.rdma.RdmaCapability;
import jcifs.internal.smb2.rdma.RdmaConnection;
import jcifs.internal.smb2.rdma.RdmaMemoryRegion;

/**
 * Unit tests for TCP RDMA provider
 */
public class TcpRdmaProviderTest {

    private TcpRdmaProvider provider;

    @BeforeEach
    public void setUp() {

import java.util.EnumSet;
import java.util.Set;

import jcifs.internal.smb2.rdma.RdmaAccess;
import jcifs.internal.smb2.rdma.RdmaCapability;
import jcifs.internal.smb2.rdma.RdmaConnection;
import jcifs.internal.smb2.rdma.RdmaMemoryRegion;
import jcifs.internal.smb2.rdma.RdmaProvider;

/**
 * TCP fallback RDMA provider.
 *
 * This provider uses regular TCP connections but maintains the RDMA

import org.slf4j.LoggerFactory;

import jcifs.internal.smb2.rdma.RdmaAccess;
import jcifs.internal.smb2.rdma.RdmaCapability;
import jcifs.internal.smb2.rdma.RdmaConnection;
import jcifs.internal.smb2.rdma.RdmaMemoryRegion;
import jcifs.internal.smb2.rdma.RdmaProvider;

/**
 * DiSNI RDMA provider for InfiniBand/RoCE networks.
 *
 * This provider uses the DiSNI (Direct Storage and Networking Interface)

     *
     * @param data data buffer to send
     * @param region registered memory region for the data
     * @throws IOException if send fails
     */
    public abstract void send(ByteBuffer data, RdmaMemoryRegion region) throws IOException;

    /**
     * Receive data using RDMA
     *
     * @param timeout timeout in milliseconds
     * @return received data buffer, or null if timeout