val choice =
          choices.firstOrNull { it.matches(peekedHeader) }
            ?: throw ProtocolException(
              "expected a matching choice but was $peekedHeader at $reader",
            )

        return choice to choice.fromDer(reader)
      }

      override fun toDer(
        writer: DerWriter,
        value: Pair<DerAdapter<*>, Any?>,