Explicit template deduction guide is required for single-parameter constructor so Substream&& is treated as a forwarding reference, and SubStream is deduced as reference type for lvalue arguments.
Declared in <serialize.h>
template<
typename Substream,
typename Params>
ParamsStream<Substream, Params>(
Substream&&,
Params const&) -> ParamsStream<Substream, Params>;