[#71458A2AE2B398BB38130BBD2BC2A27334EF8B6A]
Append params
iterator append(param_pct_view const& p);
This function appends a param to the view.
The `end()` iterator is invalidated.
url u;
u.encoded_params().append( { "first", "John" } );
Linear in `this->url().encoded_query().size()`.
Strong guarantee. Calls to allocate may throw. Exceptions thrown on invalid input.