RPC exception causes a loop with thousands of requests and log entries each second.

[daghb]

Describe the bug
When calling activateJobsCommand.Send in JobWorker returns an immediate error and casts an exception the while loop is immediately continued and a new Send is initiated just milliseconds after.

Expected behavior
A short delay should be introduced before retrying to stop server hogging.

Enviroment (please complete the following information):

• .NET Core

Additional context
Original source in JobWorker.cs / line 146 onwards

                try
                {
                    var response = await activateJobsCommand.Send(null, cancellationToken);
                    await HandleActivationResponse(input, response, jobCount);
                }
                catch (RpcException rpcException)
                {
                    LogRpcException(rpcException);
                }

should probably be

                try
                {
                    var response = await activateJobsCommand.Send(null, cancellationToken);
                    await HandleActivationResponse(input, response, jobCount);
                }
                catch (RpcException rpcException)
                {
                    LogRpcException(rpcException);
                    await Task.Delay(pollInterval, cancellationToken);
                }