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
var retry_time = 0;
for (var retry_attempt = 0; retry_attempt < 3; retry_attempt++) {
    retry_time += Math.pow(2, retry_attempt) * 1000;
    if (retry_time > 10000) {
        break;
    }
}