### Threads

#### Application's calling thread

The application-layer must block on writing I/O. We can't return from a write until we've pushed its bytes onto the socket. Otherwise, if the write fails we are unable to deliver its IOException to the application. We would have told the application layer that the write succeeded, but it didn't!

    val dataLength = 16384
    // Write the mocking script.
    peer.sendFrame().settings(Settings())
    peer.acceptFrame() // ACK
    peer.acceptFrame() // SYN_STREAM
    peer.sendFrame().headers(false, 3, headerEntries("b", "banana"))
    peer.sendFrame().data(false, 3, Buffer().write(ByteArray(dataLength)), dataLength)
    peer.sendFrame().data(false, 3, Buffer().write(ByteArray(dataLength)), dataLength)

    if (JAVA_IO_TMPDIR.value().equals("/sdcard")) {
      assertThrows(IOException.class, () -> out.write(data));
      return;
    }
    out.write(data);
    assertTrue(Arrays.equals(data, source.read()));

    out.close();
    assertThrows(IOException.class, () -> out.write(42));

    // Verify that write had no effect
    assertTrue(Arrays.equals(data, source.read()));
    out.reset();
  }

                throw new DictionaryException("Failed to write: " + oldItem + " -> " + item, e);
            }
        }

        public void write(final String line) {
            try {
                writer.write(line);
                writer.write(Constants.LINE_SEPARATOR);
            } catch (final IOException e) {
                throw new DictionaryException("Failed to write: " + line, e);
            }
        }

                throw new DictionaryException("Failed to write: " + oldItem + " -> " + item, e);
            }
        }

        public void write(final String line) {
            try {
                writer.write(line);
                writer.write(Constants.LINE_SEPARATOR);
            } catch (final IOException e) {
                throw new DictionaryException("Failed to write: " + line, e);
            }
        }

                throw new DictionaryException("Failed to write: " + oldItem + " -> " + item, e);
            }
        }

        public void write(final String line) {
            try {
                writer.write(line);
                writer.write(Constants.LINE_SEPARATOR);
            } catch (final IOException e) {
                throw new DictionaryException("Failed to write: " + line, e);
            }
        }

 */

    public void write( int b ) throws IOException {
        tmp[0] = (byte)b;
        write( tmp, 0, 1 );
    }

/**
 * Writes b.length bytes from the specified byte array to this
 * file output stream.
 *
 * @throws IOException if a network error occurs
 */

    public void write( byte[] b ) throws IOException {
        write( b, 0, b.length );
    }

// executes at least one write operation if it is closed.
//
// This can be useful within the context of HTTP. At least
// one write operation must happen to send the HTTP headers
// to the peer.
type WriteOnCloser struct {
	io.Writer
	hasWritten bool
}

func (w *WriteOnCloser) Write(p []byte) (int, error) {
	w.hasWritten = true
	return w.Writer.Write(p)
}

    this.out = out;
  }

  @Override
  public void write(int c) throws IOException {
    super.write(c);
    flush(); // flush write to TestOutputStream to get its behavior
  }

  @Override
  public void write(char[] cbuf, int off, int len) throws IOException {
    super.write(cbuf, off, len);
    flush();
  }

  @Override
  public void write(String str, int off, int len) throws IOException {

    return new FilterWriter(new OutputStreamWriter(byteSink.openStream(), UTF_8)) {
      @Override
      public void write(int c) throws IOException {
        super.write(c);
        flush();
      }

      @Override
      public void write(char[] cbuf, int off, int len) throws IOException {
        super.write(cbuf, off, len);
        flush();
      }