* `input` does not have a scheme that starts at `pos`.
     */
    private fun schemeDelimiterOffset(
      input: String,
      pos: Int,
      limit: Int,
    ): Int {
      if (limit - pos < 2) return -1

      val c0 = input[pos]
      if ((c0 < 'a' || c0 > 'z') && (c0 < 'A' || c0 > 'Z')) return -1 // Not a scheme start char.

      characters@ for (i in pos + 1 until limit) {

  fun get204Response(
    protocol: Protocol,
    mockWebServer: MockWebServer,
  ) {
    setUp(protocol, mockWebServer)
    val responseWithoutBody =
      MockResponse.Builder()
        .status("HTTP/1.1 204")
        .removeHeader("Content-Length")
        .build()
    server.enqueue(responseWithoutBody)
    val call = client.newCall(Request(server.url("/foo")))
    val response = call.execute()

    val response = call.execute()
    assertThat(response.body.string()).isEqualTo("a")
    assertThat(listener.recordedEventTypes())
      .containsExactly("CallStart", "CallEnd")
  }

  /** Response headers start, then the entire request body, then response headers end.  */
  @Test
  fun expectContinueStartsResponseHeadersEarly() {
    server.enqueue(
      MockResponse.Builder()
        .add100Continue()

    peer.acceptFrame() // SYN_STREAM
    peer.acceptFrame() // PING
    peer.sendFrame()
      .headers(false, 3, headerEntries(Header.RESPONSE_STATUS_UTF8, "HTTP/1.1 100"))
    peer.sendFrame()
      .headers(false, 3, headerEntries(Header.RESPONSE_STATUS_UTF8, "HTTP/1.1 200"))
    peer.sendFrame().ping(true, Http2Connection.AWAIT_PING, 0)
    peer.play()

    // Play it back.