public interface IGPResult 

//The data referenced in this snippet can be downloaded from the arcgis-pro-sdk-community-samples repo
//https://github.com/Esri/arcgis-pro-sdk-community-samples
async Task<IGPResult> CreateRings(EditingTemplate currentTemplate)
{
  var paramsArray = Geoprocessing.MakeValueArray(currentTemplate.MapMember.Name,
              @"C:\Data\FeatureTest\FeatureTest.gdb\Points_MultipleRingBuffer",
              new List<string> { "1000", "2000" }, "Meters", "Distance",
              "ALL", "FULL");

  IGPResult ringsResult = await Geoprocessing.ExecuteToolAsync("Analysis.MultipleRingBuffer", paramsArray);
  var messages = string.IsNullOrEmpty(gpResult.ReturnValue)
          ? $@"Error in gp tool: {gpResult.ErrorMessages}"
          : $@"Ok: {gpResult.ReturnValue}";

  return ringsResult;
}

//The data referenced in this snippet can be downloaded from the arcgis-pro-sdk-community-samples repo
//https://github.com/Esri/arcgis-pro-sdk-community-samples
string in_data = @"C:\tools\data.gdb\cities";
string cities_buff = @"E:\data\data.gdb\cities_2km";

var valueArray = Geoprocessing.MakeValueArray(in_data, cities_buff, "2000 Meters");

// to let the GP tool run asynchronously without blocking the main thread
// use the GPThread option of GPExecuteToolFlasgs
//
GPExecuteToolFlags flags = GPExecuteToolFlags.GPThread;  // instruct the tool run non-blocking GPThread
IGPResult bufferResult = await Geoprocessing.ExecuteToolAsync("Analysis.Buffer", valueArray, null, null, null, flags);