[#33925500CEFE4534D24B6AC04A7B08E44513DE71]
Assignment
params_ref& operator=(std::initializer_listinit);
After assignment, the previous contents of the query parameters are replaced by the contents of the initializer-list.
None of character buffers referenced by `init` may overlap the character buffer of the underlying url, or else the behavior is undefined.
this->assign( init );
Linear in `init.size()`.
Strong guarantee. Calls to allocate may throw.