private static int availableCapacity(Buffer buffer) {
    return buffer.capacity() - buffer.limit();
  }

  /**
   * Flips the buffer output buffer so we can start reading bytes from it. If we are starting to
   * drain because there was overflow, and there aren't actually any characters to drain, then the
   * overflow must be due to a small output buffer.
   */
  private void startDraining(boolean overflow) {

        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");
    }

  @BeforeEach
  fun setUp() {
    if (connectionType == H2) {
      platform.assumeHttp2Support()
    }

    // Sockets on some platforms can have large buffers that mean writes do not block when
    // required. These socket factories explicitly set the buffer sizes on sockets created.
    server = MockWebServer()
    server.serverSocketFactory =
      object : DelegatingServerSocketFactory(ServerSocketFactory.getDefault()) {

    T pivotValue = uncheckedCastNullableTToT(buffer[pivotIndex]);
    buffer[pivotIndex] = buffer[right];

    int pivotNewIndex = left;
    for (int i = left; i < right; i++) {
      if (comparator.compare(uncheckedCastNullableTToT(buffer[i]), pivotValue) < 0) {
        swap(pivotNewIndex, i);
        pivotNewIndex++;
      }
    }
    buffer[right] = buffer[pivotNewIndex];
    buffer[pivotNewIndex] = pivotValue;

            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));

            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 {

    }

    @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

    READY,

    /** We haven't yet computed or have already returned the element. */
    NOT_READY,

    /** We have reached the end of the data and are finished. */
    DONE,

    /** We've suffered an exception and are kaput. */
    FAILED,
  }

  private @Nullable T next;

  /**
   * Returns the next element. <b>Note:</b> the implementation must call {@link #endOfData()} when

        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;
    }