if (!stream.source.exhausted()) throw AssertionError("expected exhausted")
      }
    }

  fun cancelStream() =
    apply {
      actions += { stream -> stream.cancel() }
    }

  fun requestIOException() =
    apply {
      actions += { stream ->
        try {
          stream.source.exhausted()
          throw AssertionError("expected IOException")
        } catch (expected: IOException) {
        }