[#7584DE9369114B8DE192D06BB986479ECD770AA3]
Return the number of matching keys
std::size_t count( pct_string_view key, ignore_case_param ic = = {}) const noexcept;
This function examines the parameters in the container to find the number of matches 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().count( "first" ) == 1 );
Linear in `this->buffer().size()`.
Exceptions thrown on invalid input.