) {
    val cookieStrings = mutableListOf<String>()
    for (cookie in cookies) {
      cookieStrings.add(cookieToString(cookie, true))
    }
    val multimap = mapOf("Set-Cookie" to cookieStrings)
    try {
      cookieHandler.put(url.toUri(), multimap)
    } catch (e: IOException) {
      Platform.get().log("Saving cookies failed for " + url.resolve("/...")!!, WARN, e)
    }
  }

    val names: Set<String> = headers.names()
    val values: List<String> = headers.values("")
    val byteCount: Long = headers.byteCount()
    val builder: Headers.Builder = headers.newBuilder()
    val multimap: Map<String, List<String>> = headers.toMultimap()
  }

  @Test
  fun headersBuilder() {
    var builder: Headers.Builder = Headers.Builder()
    builder = builder.add("")
    builder = builder.add("", "")

Typically HTTP headers work like a `Map<String, String>`: each field has one value or none. But some headers permit multiple values, like Guava's [Multimap](https://guava.dev/releases/23.0/api/docs/com/google/common/collect/Multimap.html). For example, it's legal and common for an HTTP response to supply multiple `Vary` headers. OkHttp's APIs attempt to make both cases comfortable.