[#CAD809F6272B6BFE2F49A0FBC89639922E01ACD6]
Return true if a matching key exists
bool contains( pct_string_view key, ignore_case_param ic = = {}) const noexcept;
This function examines the parameters in the container to find a match for the specified key, which may contain percent escapes. The comparison is performed as if all escaped characters were decoded first.
assert( url_view( "?first=John&last=Doe" ).encoded_params().contains( "first" ) );
Linear in `this->buffer().size()`.
Exceptions thrown on invalid input.