/// Serialize Args... to channel C, but do not call C.send().
///
/// Returns an error (on serialization failure) or a pair of:
- /// (1) A future Expected<T> (or future<bool> for void functions), and
+ /// (1) A future Expected<T> (or future<Error> for void functions), and
/// (2) A sequence number.
///
/// This utility function is primarily used for single-threaded mode support,
/// Serialize Args... to channel C, but do not call send.
/// Returns an error if serialization fails, otherwise returns a
- /// std::future<Expected<T>> (or a future<bool> for void functions).
+ /// std::future<Expected<T>> (or a future<Error> for void functions).
template <typename Func, typename... ArgTs>
Expected<AsyncCallResult<Func>> appendCallAsync(ChannelT &C,
const ArgTs &... Args) {