create method
Creates a new function.
If a function with the given name already exists in the specified project,
the long running operation will return ALREADY_EXISTS error.
request - The metadata request object.
Request parameters:
parent - Required. The project and location in which the function should
be created, specified in the format projects / * /locations / * 
Value must have pattern ^projects/\[^/\]+/locations/\[^/\]+$.
functionId - The ID to use for the function, which will become the final
component of the function's resource name. This value should be 4-63
characters, and valid characters are /a-z-/.
$fields - Selector specifying which fields to include in a partial
response.
Completes with a Operation.
Completes with a commons.ApiRequestError if the API endpoint returned an error.
If the used http.Client completes with an error when making a REST call,
this method will complete with the same error.
Implementation
async.Future<Operation> create(
  Function_ request,
  core.String parent, {
  core.String? functionId,
  core.String? $fields,
}) async {
  final body_ = convert.json.encode(request);
  final queryParams_ = <core.String, core.List<core.String>>{
    if (functionId != null) 'functionId': [functionId],
    if ($fields != null) 'fields': [$fields],
  };
  final url_ = 'v2/' + core.Uri.encodeFull('$parent') + '/functions';
  final response_ = await _requester.request(
    url_,
    'POST',
    body: body_,
    queryParams: queryParams_,
  );
  return Operation.fromJson(response_ as core.Map<core.String, core.dynamic>);
}