create method
      
Future<Operation> 
create(
    
- Connection request,
 - String parent, {
 - String? connectionId,
 - String? $fields,
 
Creates a new Connection in a given project and location.
request - The metadata request object.
Request parameters:
parent - Required. Parent resource of the Connection, of the form:
projects / * /locations / * 
Value must have pattern ^projects/\[^/\]+/locations/\[^/\]+$.
connectionId - Required. Identifier to assign to the Connection. Must be
unique within scope of the parent resource.
$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(
  Connection request,
  core.String parent, {
  core.String? connectionId,
  core.String? $fields,
}) async {
  final body_ = convert.json.encode(request);
  final queryParams_ = <core.String, core.List<core.String>>{
    if (connectionId != null) 'connectionId': [connectionId],
    if ($fields != null) 'fields': [$fields],
  };
  final url_ = 'v1/' + core.Uri.encodeFull('$parent') + '/connections';
  final response_ = await _requester.request(
    url_,
    'POST',
    body: body_,
    queryParams: queryParams_,
  );
  return Operation.fromJson(response_ as core.Map<core.String, core.dynamic>);
}