private var refusedStreamCount = 0

  /**
   * The maximum number of concurrent streams that can be carried by this connection. If
   * `allocations.size() < allocationLimit` then new streams can be created on this connection.
   */
  internal var allocationLimit = 1
    private set

  /** Current calls carried by this connection. */
  val calls = mutableListOf<Reference<RealCall>>()

  /** Returns the HTTP status message. */
  @get:JvmName("message") val message: String,
  /** Returns the HTTP status code. */
  @get:JvmName("code") val code: Int,
  /**
   * Returns the TLS handshake of the connection that carried this response, or null if the
   * response was received without TLS.
   */
  @get:JvmName("handshake") val handshake: Handshake?,
  /** Returns the HTTP headers. */
  @get:JvmName("headers") val headers: Headers,
  /**