withLock {
      while (headersQueue.isEmpty() && errorCode == null) {
        val doReadTimeout = callerIsIdle || doReadTimeout()
        if (doReadTimeout) {
          readTimeout.enter()
        }
        try {
          waitForIo()
        } finally {
          if (doReadTimeout) {
            readTimeout.exitAndThrowIfTimedOut()
          }
        }
      }