.body("ABCD")
        .build(),
    )
    val call = client.newCall(newRequest("/"))
    val response = call.execute()
    val inputStream = response.body.byteStream()
    assertThat(inputStream.read().toChar()).isEqualTo('A')
    call.cancel()
    assertFailsWith<IOException> {
      // Reading 'B' may succeed if it's buffered.
      inputStream.read()

      assertThat(expected.message).isEqualTo("Unexpected char 0x20 at 1 in header name: a b")
    }
  }

  @Test
  fun requestHeaderNameWithTabForbidden() {
    assertFailsWith<IllegalArgumentException> {
      Request.Builder().addHeader("a\tb", "c")
    }.also { expected ->
      assertThat(expected.message).isEqualTo("Unexpected char 0x09 at 1 in header name: a\tb")
    }
  }

  @Test