isOptionalParam method
Checks whether the placeholder with the given key is optional.
Throws ApiError when the key is not present in the pattern.
Implementation
bool isOptionalParam(String key) {
final segment = _segments.firstWhere(
(element) => element is _PLSegment && element.key == key,
orElse: () => throw ApiError(
'Placeholder param "$key" not present in pattern: $pattern'))
as _PLSegment;
return segment.optional;
}