initiateBackup method
      
Future<InitiateBackupResponse> 
initiateBackup(
    
- InitiateBackupRequest request,
- String dataSource, {
- String? $fields,
Internal only.
Initiates a backup.
request - The metadata request object.
Request parameters:
dataSource - Required. The resource name of the instance, in the format
'projects / * /locations / * /backupVaults / * /dataSources/'.
Value must have pattern
^projects/\[^/\]+/locations/\[^/\]+/backupVaults/\[^/\]+/dataSources/\[^/\]+$.
$fields - Selector specifying which fields to include in a partial
response.
Completes with a InitiateBackupResponse.
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<InitiateBackupResponse> initiateBackup(
  InitiateBackupRequest request,
  core.String dataSource, {
  core.String? $fields,
}) async {
  final body_ = convert.json.encode(request);
  final queryParams_ = <core.String, core.List<core.String>>{
    if ($fields != null) 'fields': [$fields],
  };
  final url_ = 'v1/' + core.Uri.encodeFull('$dataSource') + ':initiateBackup';
  final response_ = await _requester.request(
    url_,
    'POST',
    body: body_,
    queryParams: queryParams_,
  );
  return InitiateBackupResponse.fromJson(
    response_ as core.Map<core.String, core.dynamic>,
  );
}