assertSame(a, first, "First get should return first cached buffer");
        assertSame(c, second, "Second get should return second cached buffer");
        assertNotSame(d, third, "Third get should allocate a new buffer (not the dropped one)");
        assertEquals(3, third.length, "Allocated buffer length matches configured maximum size");
    }

            byte[][] buffers = new byte[][] { new byte[8], new byte[8] };

            when(src.toString()).thenReturn("smb://src");
            when(dest.toString()).thenReturn("smb://dest");

            // Act + Assert
            SmbException ex =
                    assertThrows(SmbException.class, () -> SmbCopyUtil.copyFile(src, dest, buffers, 8, new WriterThread(), sh, dh));

    // Create a payload which will overflow the normal payload byte size.
    val payload = Buffer()
    while (payload.completeSegmentByteCount() <= PAYLOAD_BYTE_MAX) {
      payload.writeByte('0'.code)
    }
    serverWriter.writeMessageFrame(OPCODE_BINARY, payload.snapshot())

    // Write directly to the unbuffered sink. This ensures it will become single frame.
    assertData("827e") // 'e' == 4-byte follow-up length.

            when(mockSmbPipeHandleInternal.recv(buf, 0, buf.length)).thenAnswer(invocation -> {
                byte[] buffer = invocation.getArgument(0);
                buffer[0] = 5; // Valid PDU version
                buffer[1] = 0; // Valid PDU type
                Encdec.enc_uint16le((short) 50, buffer, 8); // Fragment length
                return 30; // Initial bytes received
            });

			// with dead end because tcp-keepalive is not fired when there is data in the socket buffer.
			//    https://blog.cloudflare.com/when-tcp-sockets-refuse-to-die/
			// This is a sensitive configuration, it is better to set it to high values, > 60 secs since it can
			// affect clients reading data with a very slow pace  (disappropriate with socket buffer sizes)
			if opts.UserTimeout > 0 {

        for (int i = 8; i < 16; i++) {
            buffer[i] = (byte) (i * 2);
        }

        // Mock number of links (4 bytes)
        buffer[16] = 0x01;
        buffer[17] = 0x00;
        buffer[18] = 0x00;
        buffer[19] = 0x00;

        // Mock delete pending and directory flags
        buffer[20] = 0x00;
        buffer[21] = 0x00;

        return buffer;
    }

/**
 * Internal API for managing reusable buffers
 *
 * @author mbechler
 *
 * <p>This interface is intended for internal use.</p>
 */
public interface BufferCache {

    /**
     * Gets a buffer from the cache or creates a new one if the cache is empty.
     *
     * @return a buffer from the cache, or a new one
     */
    byte[] getBuffer();

    /**
     * Return a buffer to the cache
     *

        assertEquals((byte) 0xEF, buffer[0]); // Little-endian
        assertEquals((byte) 0xCD, buffer[1]);
        assertEquals((byte) 0xAB, buffer[2]);
        assertEquals((byte) 0x89, buffer[3]);
        assertEquals((byte) 0x67, buffer[4]);
        assertEquals((byte) 0x45, buffer[5]);
        assertEquals((byte) 0x23, buffer[6]);
        assertEquals((byte) 0x01, buffer[7]);

        ndrBuffer.setIndex(0);

    // requireNonNull accommodates Android's @RecentlyNullable annotation on ThreadLocal.get
    return requireNonNull(DEST_TL.get());
  }

  /**
   * A thread-local destination buffer to keep us from creating new buffers. The starting size is
   * 1024 characters. If we grow past this we don't put it back in the threadlocal, we just keep
   * going and grow as needed.
   */
  private static final ThreadLocal<char[]> DEST_TL =

    }

    @Override
    protected synchronized SmbFileHandleImpl ensureOpen() throws CIFSException {
        return this.handle.ensureOpen();
    }

    /**
     * This stream class is unbuffered. Therefore this method will always
     * return 0 for streams connected to regular files. However, a
     * stream created from a Named Pipe this method will query the server using a