Insert elements
                iterator
insert(
    iterator before,
    const param_view& p);            
        Declared in file <src/params_ref.cpp> at line 64
This function inserts a param before the specified position.
All iterators that are equal to `before` or come after are invalidated.
Linear in `this->url().encoded_query().size()`.
Strong guarantee. Calls to allocate may throw.