}

  override fun appendingSink(
    file: Path,
    mustExist: Boolean,
  ): Sink = FaultySink(super.appendingSink(file, mustExist), file)

  override fun sink(
    file: Path,
    mustCreate: Boolean,
  ): Sink = FaultySink(super.sink(file, mustCreate), file)

  inner class FaultySink(sink: Sink, private val file: Path) : ForwardingSink(sink) {
    override fun write(
      source: Buffer,
      byteCount: Long,
    ) {

    TestCharSink sink = new TestCharSink();

    assertFalse(sink.wasStreamOpened() || sink.wasStreamClosed());

    assertEquals(STRING.length(), source.copyTo(sink));
    assertTrue(source.wasStreamOpened() && source.wasStreamClosed());
    assertTrue(sink.wasStreamOpened() && sink.wasStreamClosed());

    assertEquals(STRING, sink.getString());
  }

        boolean value = random.nextBoolean();
        for (PrimitiveSink sink : sinks) {
          sink.putBoolean(value);
        }
      }
    },
    PUT_BYTE() {
      @Override
      void performAction(Random random, Iterable<? extends PrimitiveSink> sinks) {
        int value = random.nextInt();
        for (PrimitiveSink sink : sinks) {
          sink.putByte((byte) value);
        }
      }
    },

  /**
   * Writes all the given bytes to this sink.
   *
   * @throws IOException if an I/O occurs while writing to this sink
   */
  public void write(byte[] bytes) throws IOException {
    checkNotNull(bytes);

    try (OutputStream out = openStream()) {
      out.write(bytes);
    }
  }

  /**
   * Writes all the bytes from the given {@code InputStream} to this sink. Does not close {@code
   * input}.
   *

    fun writeTo(editor: DiskLruCache.Editor) {
      editor.newSink(ENTRY_METADATA).buffer().use { sink ->
        sink.writeUtf8(url.toString()).writeByte('\n'.code)
        sink.writeUtf8(requestMethod).writeByte('\n'.code)
        sink.writeDecimalLong(varyHeaders.size.toLong()).writeByte('\n'.code)
        for (i in 0 until varyHeaders.size) {
          sink.writeUtf8(varyHeaders.name(i))
            .writeUtf8(": ")

  /**
   * Returns a sink that can be used to write data to the peer.
   *
   * @throws IllegalStateException if this stream was initiated by the peer and a [writeHeaders] has
   *     not yet been sent.
   */
  fun getSink(): Sink {
    this.withLock {
      check(hasResponseHeaders || isLocallyInitiated) {
        "reply before requesting the sink"
      }
    }
    return sink
  }

    randomAccessFile!!.getChannel().force(false)
    val source = file!!.source().buffer()
    return source.readByteString()
  }

  private fun write(data: ByteString) {
    val sink = file!!.sink().buffer()
    sink.write(data)
    sink.close()
  }

      }

      override fun writeTo(sink: BufferedSink) {
        sink.writeUtf8("<el")
        sink.flush()
        throw IOException("failed to stream the XML")
      }
    }

    class ValidRequestBody : RequestBody() {
      override fun contentType(): MediaType {
        return "application/xml".toMediaType()
      }

      override fun writeTo(sink: BufferedSink) {
        sink.writeUtf8("<element/>")

```Python hl_lines="9"
{!../../docs_src/query_params/tutorial001.py!}
```

Query-Parameter (Deutsch: Abfrage-Parameter) sind die Schlüssel-Wert-Paare, die nach dem `?` in einer URL aufgelistet sind, getrennt durch `&`-Zeichen.

Zum Beispiel sind in der URL:

```
http://127.0.0.1:8000/items/?skip=0&limit=10

`Body` gibt auch Instanzen einer Unterklasse von `FieldInfo` zurück. Und später werden Sie andere sehen, die Unterklassen der `Body`-Klasse sind.

Denken Sie daran, dass `Query`, `Path` und andere von `fastapi` tatsächlich Funktionen sind, die spezielle Klassen zurückgeben.

///

/// tip | "Tipp"