assertEquals("Should have 2 payloads", 2, multiAnnotation.payload().length);
        assertEquals("First payload should be TestPayload", TestPayload.class, multiAnnotation.payload()[0]);
        assertEquals("Second payload should be AnotherTestPayload", AnotherTestPayload.class, multiAnnotation.payload()[1]);
    }

    // Test ProtocolType enum values

        assertEquals("Should have 2 payloads", 2, multiAnnotation.payload().length);
        assertEquals("First payload should be TestPayload", TestPayload.class, multiAnnotation.payload()[0]);
        assertEquals("Second payload should be AnotherTestPayload", AnotherTestPayload.class, multiAnnotation.payload()[1]);
    }

    // Additional test interfaces for multiple groups/payloads test
    private interface AnotherTestGroup {

    val payload = Buffer()
    while (payload.completeSegmentByteCount() <= PAYLOAD_BYTE_MAX) {
      payload.writeByte('0'.code)
    }
    serverWriter.writeMessageFrame(OPCODE_BINARY, payload.snapshot())

    // Write directly to the unbuffered sink. This ensures it will become single frame.
    assertData("827e") // 'e' == 4-byte follow-up length.
    assertData(format("%04X", payload.completeSegmentByteCount()))

  /** Send a ping with the supplied [payload]. */
  @Throws(IOException::class)
  fun writePing(payload: ByteString) {
    writeControlFrame(OPCODE_CONTROL_PING, payload)
  }

  /** Send a pong with the supplied [payload]. */
  @Throws(IOException::class)
  fun writePong(payload: ByteString) {
    writeControlFrame(OPCODE_CONTROL_PONG, payload)
  }

  /**

  fun assertTextMessage(payload: String?) {
    assertThat(nextEvent()).isEqualTo(Message(string = payload))
  }

  fun assertBinaryMessage(payload: ByteString?) {
    assertThat(nextEvent()).isEqualTo(Message(payload))
  }

  fun assertPing(payload: ByteString) {
    assertThat(nextEvent()).isEqualTo(Ping(payload))
  }

  fun assertPong(payload: ByteString) {

    /**
     * The validation groups this constraint belongs to.
     * @return the groups
     */
    Class<?>[] groups() default {};

    /**
     * The payload associated with this constraint.
     * @return the payload
     */
    Class<? extends Payload>[] payload() default {};

    /**
     * Gets the configuration key for the minimum size constraint.
     * @return name of size the element must be higher or equal to
     */

  internal const val OPCODE_FLAG_CONTROL = 8

  /**
   * Byte 1 flag for whether the payload data is masked.
   *
   * If this flag is set, the next four
   * bytes represent the mask key. These bytes appear after any additional bytes specified by [B1_MASK_LENGTH].
   */
  internal const val B1_FLAG_MASK = 128

  /**
   * Byte 1 mask for the payload length.
   *
   * If this value is [PAYLOAD_SHORT], the next two

    /**
     * The validation groups this constraint belongs to.
     * @return the groups
     */
    Class<?>[] groups() default {};

    /**
     * The payload associated with this constraint.
     * @return the payload
     */
    Class<? extends Payload>[] payload() default {};

  interface FrameCallback {
    @Throws(IOException::class)
    fun onReadMessage(text: String)

    @Throws(IOException::class)
    fun onReadMessage(bytes: ByteString)

    fun onReadPing(payload: ByteString)

    fun onReadPong(payload: ByteString)

    fun onReadClose(
      code: Int,
      reason: String,
    )
  }

  /**
   * Process the next protocol frame.
   *

    /**
     * The validation groups.
     *
     * @return the validation groups
     */
    Class<?>[] groups() default {};

    /**
     * The payload for constraint.
     *
     * @return the payload
     */
    Class<? extends Payload>[] payload() default {};