When requests to Step Function fail, Workflow Service performs exponential backoff retries to notify Step Function service. Number of retries = 3 The total duration of all attempts doesn't exceed 10 seconds, the processing must not exceed the message visibility timeout.

Script
const WAIT_BETWEEN_RETRIES_IN_SECONDS = 1;
const NUMBER_OF_RETRIES = 3;
const MAX_DURATION = 10;

const numberOfRetries = Math.min(Math.ceil(Math.log2(MAX_DURATION)), NUMBER_OF_RETRIES);

var delay = WAIT_BETWEEN_RETRIES_IN_SECONDS * Math.pow(2, numberOfRetries);

return callback(null, {
  delay: delay,
  numberOfRetries: numberOfRetries
});