}

  @Test fun ofRejectsNullChar() {
    assertFailsWith<IllegalArgumentException> {
      headersOf("User-Agent", "Square\u0000OkHttp")
    }
  }

  @Test fun ofMapThrowsOnEmptyName() {
    assertFailsWith<IllegalArgumentException> {
      mapOf("" to "OkHttp").toHeaders()
    }
  }

  @Test fun ofMapThrowsOnBlankName() {
    assertFailsWith<IllegalArgumentException> {