private val postponedRoutes = mutableListOf<Route>()

  init {
    resetNextProxy(address.url, address.proxy)
  }

  /**
   * Returns true if there's another set of routes to attempt. Every address has at least one route.
   */
  operator fun hasNext(): Boolean = hasNextProxy() || postponedRoutes.isNotEmpty()

  @Throws(IOException::class)
  operator fun next(): Selection {
    if (!hasNext()) throw NoSuchElementException()

  fun onePartRequired() {
    assertFailsWith<IllegalStateException> {
      MultipartBody.Builder().build()
    }.also { expected ->
      assertThat(expected.message)
        .isEqualTo("Multipart body must have at least one part.")
    }
  }

  @Test
  fun singlePart() {
    val expected =
      """
      |--123
      |
      |Hello, World!
      |--123--
      |
      """.trimMargin().replace("\n", "\r\n")

part of its distribution, then any Derivative Works that You distribute must include a readable copy of the attribution notices contained within such NOTICE file, excluding those notices that do not pertain to any part of the Derivative Works, in at least one of the following places: within a NOTICE text file distributed as part of the Derivative Works; within the Source form or documentation, if provided along with the Derivative Works; or, within a display generated by the Derivative Works, if and...

    }

  /**
   * The number of segments in this URL's path. This is also the number of slashes in this URL's
   * path, like 3 in `http://host/a/b/c`. This is always at least 1.
   *
   * | URL                  | `pathSize()` |
   * | :------------------- | :----------- |
   * | `http://host/`       | `1`          |
   * | `http://host/a/b/c`  | `3`          |

        return true
      }
    }

    // If we have a routes left, use 'em.
    if (routeSelection?.hasNext() == true) return true

    // If we haven't initialized the route selector yet, assume it'll have at least one route.
    val localRouteSelector = routeSelector ?: return true

    // If we do have a route selector, use its routes.
    return localRouteSelector.hasNext()
  }

  /**

        apply {
          parts += part
        }

      /** Assemble the specified parts into a request body. */
      fun build(): MultipartBody {
        check(parts.isNotEmpty()) { "Multipart body must have at least one part." }
        return MultipartBody(boundary, type, parts.toImmutableList())
      }
    }

  companion object {
    /**

    cache.close()
    createNewCacheWithSize(10)
    set("a", "a", "a")
    set("b", "b", "b")
    set("c", "c", "c")
    set("d", "d", "d")
    set("e", "e", "e")
    cache["b"]!!.close() // 'B' is now least recently used.

    // Causing the size to grow to 12 should evict 'A'.
    set("f", "f", "f")
    // Causing the size to grow to 12 should evict 'C'.
    set("g", "g", "g")
    cache.flush()

        addressState.concurrentCallCapacity += connection.allocationLimit
      }
    }

    // Find the longest-idle connections in 2 categories:
    //
    //  1. OLD: Connections that have been idle for at least keepAliveDurationNs. We close these if
    //     we find them, regardless of what the address policies need.
    //
    //  2. EVICTABLE: Connections not required by any address policy. This matches connections that

        if (closed) return
        outFinished = errorCode == null
      }
      if (!sink.finished) {
        // We have 0 or more frames of data, and 0 or more frames of trailers. We need to send at
        // least one frame with the END_STREAM flag set. That must be the last frame, and the
        // trailers must be sent after all of the data.
        val hasData = sendBuffer.size > 0L
        val hasTrailers = trailers != null

    if (size > maxSize || journalRebuildRequired()) {
      cleanupQueue.schedule(cleanupTask)
    }
  }

  /**
   * We only rebuild the journal when it will halve the size of the journal and eliminate at least
   * 2000 ops.
   */
  private fun journalRebuildRequired(): Boolean {
    val redundantOpCompactThreshold = 2000
    return redundantOpCount >= redundantOpCompactThreshold &&