* `write(data)`: Writes `data` (`str` or `bytes`) to the file.
* `read(size)`: Reads `size` (`int`) bytes/characters of the file.
* `seek(offset)`: Goes to the byte position `offset` (`int`) in the file.
    * E.g., `await myfile.seek(0)` would go to the start of the file.
    * This is especially useful if you run `await myfile.read()` once and then need to read the contents again.
* `close()`: Closes the file.

    val source = relay.newSource()
    val sourceBuffer = Buffer()
    assertThat(source!!.read(sourceBuffer, 5)).isEqualTo(5)
    assertThat(sourceBuffer.readUtf8()).isEqualTo("abcde")
    assertThat(source.read(sourceBuffer, 1024)).isEqualTo(8)
    assertThat(sourceBuffer.readUtf8()).isEqualTo("fghijklm")
    assertThat(source.read(sourceBuffer, 1024)).isEqualTo(-1)
    assertThat(sourceBuffer.size).isEqualTo(0)
    source.close()

            SMBUtil.writeInt2(17, buffer, 0); // Structure size
            SMBUtil.writeInt2(0, buffer, 2); // Reserved
            SMBUtil.writeInt4(-1, buffer, 4); // Count (will be read as unsigned)
            SMBUtil.writeInt4(-2, buffer, 8); // Remaining (will be read as unsigned)
            SMBUtil.writeInt4(0, buffer, 12); // WriteChannelInfoOffset/Length

            int bytesRead = response.readBytesWireFormat(buffer, 0);

    val buffer = Buffer()
    operator.read(6, buffer, 21)
    operator.read(36, buffer, 1)
    operator.read(5, buffer, 5)
    operator.read(28, buffer, 8)
    operator.read(17, buffer, 10)
    operator.read(36, buffer, 2)
    operator.read(2, buffer, 4)
    operator.write(0, buffer, buffer.size)
    operator.read(0, buffer, 12)
    operator.read(47, buffer, 3)
    operator.read(45, buffer, 2)
    operator.read(47, buffer, 3)

    }

    @Override
    public synchronized int read() throws IOException {
        if (read(tmp, 0, 1) < 0) {
            return -1;
        }
        return tmp[0] & 0xFF;
    }

    @Override
    public synchronized int read(final byte[] b) throws IOException {
        return read(b, 0, b.length);
    }

    /* This method will not return until len bytes have been read
     * or the stream has been closed.
     */

/**
 * SMB1 Read AndX request message.
 *
 * This command is used to read data from a file that has been
 * previously opened with an Open command.
 */
public class SmbComReadAndX extends AndXServerMessageBlock {

    private long offset;
    private int fid;
    int openTimeout;
    int maxCount, minCount, remaining;

    /**
     * Constructs a Read AndX request.
     *

     * @param len length of data to read
     * @return number of bytes read
     */
    protected abstract int readSetupWireFormat(byte[] buffer, int bufferIndex, int len);

    /**
     * Reads parameters from wire format
     * @param buffer source buffer
     * @param bufferIndex starting index in source buffer
     * @param len length of data to read
     * @return number of bytes read

    assertEquals(0, ticker.read());
    assertEquals(10, ticker.read());
    assertEquals(20, ticker.read());
  }

  public void testAutoIncrementStep_millis() {
    FakeTicker ticker = new FakeTicker().setAutoIncrementStep(1, MILLISECONDS);
    assertEquals(0, ticker.read());
    assertEquals(1000000, ticker.read());
    assertEquals(2000000, ticker.read());
  }

 *       block indefinitely or fail if the source creates an infinite reader.
 *   <li><b>Non-destructive:</b> A <i>destructive</i> reader will consume or otherwise alter the
 *       source as they are read from it. A source that provides such readers will not be reusable,
 *       and operations that read from the stream (including {@link #length()}, in some

 *       block indefinitely or fail if the source creates an infinite reader.
 *   <li><b>Non-destructive:</b> A <i>destructive</i> reader will consume or otherwise alter the
 *       source as they are read from it. A source that provides such readers will not be reusable,
 *       and operations that read from the stream (including {@link #length()}, in some