Convenience constructor for an accept whose collected content is built by serializing a typed struct T (symmetric with contentAs!T). The struct fields become the {name: value} content map, so accept!T(v).contentAs!T round-trips.
Convenience constructor for an accept whose collected content is built by serializing a typed struct T (symmetric with contentAs!T). The struct fields become the {name: value} content map, so accept!T(v).contentAs!T round-trips.