describeApplication method
Describes the application.
May throw ResourceNotFoundException. May throw ValidationException. May throw InternalServerException.
Parameter resourceGroupName :
The name of the resource group.
Implementation
Future<DescribeApplicationResponse> describeApplication({
  required String resourceGroupName,
}) async {
  ArgumentError.checkNotNull(resourceGroupName, 'resourceGroupName');
  _s.validateStringLength(
    'resourceGroupName',
    resourceGroupName,
    1,
    256,
    isRequired: true,
  );
  final headers = <String, String>{
    'Content-Type': 'application/x-amz-json-1.1',
    'X-Amz-Target': 'EC2WindowsBarleyService.DescribeApplication'
  };
  final jsonResponse = await _protocol.send(
    method: 'POST',
    requestUri: '/',
    exceptionFnMap: _exceptionFns,
    // TODO queryParams
    headers: headers,
    payload: {
      'ResourceGroupName': resourceGroupName,
    },
  );
  return DescribeApplicationResponse.fromJson(jsonResponse.body);
}