func (w *writerAt) WriteAt(b []byte, offset int64) (n int, err error) {
	w.m.Lock()
	defer w.m.Unlock()

	if w.nextOffset == offset {
		n, err = w.w.Write(b)
		w.nextOffset += int64(n)
	} else {
		if offset > w.nextOffset+ftpMaxWriteOffset {
			return 0, fmt.Errorf("write offset %d is too far ahead of next offset %d", offset, w.nextOffset)
		}
		w.buffer[offset] = make([]byte, len(b))
		copy(w.buffer[offset], b)
		n = len(b)

        SMBUtil.writeInt4(32, dst, dstIndex); // DataLength
        dstIndex += 4;

        // Write context name
        System.arraycopy(CONTEXT_NAME_BYTES, 0, dst, dstIndex, 4);
        dstIndex += 4;

        // Padding to align data to 8-byte boundary
        dstIndex += 4;

        // Write lease V1 data (32 bytes total)
        leaseKey.encode(dst, dstIndex); // LeaseKey (16 bytes)
        dstIndex += 16;

	return &pooledFlateWriter{fw: fw}
}

type pooledFlateWriter struct {
	mu sync.Mutex // guards Close and Write
	fw *flate.Writer
}

func (w *pooledFlateWriter) Write(p []byte) (n int, err error) {
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.fw == nil {
		return 0, errors.New("Write after Close")
	}
	return w.fw.Write(p)
}

func (w *pooledFlateWriter) Close() error {
	w.mu.Lock()
	defer w.mu.Unlock()
	var err error

// If nn < len(p), it also returns an error explaining
// why the write is short.
func (b *Writer) Write(p []byte) (nn int, err error) {
	for len(p) > b.Available() && b.err == nil {
		var n int
		if b.Buffered() == 0 {
			// Large write, empty buffer.
			// Write directly from p to avoid copy.
			n, b.err = b.wr.Write(p)
		} else {
			n = copy(b.buf[b.n:], p)
			b.n += n
			b.Flush()
		}
		nn += n

            // Read the response
            int bytesRead = echoResponse.readBytesWireFormat(buffer, bufferIndex);
            assertEquals(0, bytesRead);

            // Write response (echo responses don't write data)
            int bytesWritten = echoResponse.writeBytesWireFormat(buffer, 0);
            assertEquals(0, bytesWritten);

            // Mark as received
            echoResponse.received();

        
        writeInt4(buffer, offset + 12, dataOffset - offset);  // DataOffset
        
        // Write context name
        System.arraycopy(getName().getBytes(), 0, buffer, offset + 16, getName().length());
        
        // Write lease data
        System.arraycopy(leaseKey.getKey(), 0, buffer, dataOffset, 16);  // LeaseKey

        }

        @Test
        @DisplayName("Should handle write at buffer boundary")
        void testWriteAtBufferBoundary() {
            request.setReadLength(1024);

            byte[] buffer = new byte[100];

            // Try to write at position that would exceed buffer

            assertDoesNotThrow(() -> request.setRemainingBytes(1024));
            assertDoesNotThrow(() -> request.setRemainingBytes(Integer.MAX_VALUE));
        }

        @Test
        @DisplayName("Should set write flags")
        void testSetWriteFlags() {
            assertDoesNotThrow(() -> request.setWriteFlags(0));
            assertDoesNotThrow(() -> request.setWriteFlags(0x01));

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.io;

import static com.google.common.io.FileBackedOutputStreamTest.write;

import com.google.common.testing.GcFinalization;
import java.io.File;
import org.jspecify.annotations.NullUnmarked;

/**
 * Android-incompatible tests for {@link FileBackedOutputStream}.
 *

        // Cannot test getConfig() as it's protected
    }

    @Nested
    @DisplayName("writeBytesWireFormat tests")
    class WriteBytesWireFormatTests {

        @Test
        @DisplayName("Should return 0 for write bytes")
        void testWriteBytesWireFormat() {
            // Given
            byte[] dst = new byte[100];
            int dstIndex = 0;

            // When