RescheduleStrategy.cs

public class RescheduleStrategy
{
    private const string RetryAttemptPropertyName = "retry-attempt";
    private const int MaxRetryAttempts = 5;
    private const int Exponent = 2;
    private readonly Random _random = new Random();
    private readonly IQueueClient _queueClientImplementation;
    private readonly TimeSpan _initialDelay = TimeSpan.FromSeconds(5);

    public async Task ScheduleRetryAsync(Message message)
    {
        int attempt = message.UserProperties.ContainsKey(RetryAttemptPropertyName)
            ? (int)message.UserProperties[RetryAttemptPropertyName] + 1
            : 1;

        if (!CanDelay(attempt))
        {
            await _queueClientImplementation.DeadLetterAsync(
                message.SystemProperties.LockToken,
                "Exceed retry attempts.");
            return;
        }

        // Clone message to copy properties and content
        Message messageCopy = message.Clone();
        // Have to set new id if message duplicate detection is turned on
        // Otherwise message will be ignored
        messageCopy.MessageId = Guid.NewGuid().ToString();
        // Enhance message with new retry attempt
        message.UserProperties[RetryAttemptPropertyName] = attempt;

        // It's preferred to use transaction scope for rescheduling
        // to perform both scheduling and completion of the initial message simultaneously
        // However it's only possible if the same queue is used
        using (var scope = new TransactionScope())
        {
            await _queueClientImplementation.ScheduleMessageAsync(
                messageCopy,
                DateTimeOffset.UtcNow + GetDelay(attempt));
            await _queueClientImplementation.CompleteAsync(message.SystemProperties.LockToken);
            scope.Complete();
        }
    }

    private bool CanDelay(int attempt) => attempt <= MaxRetryAttempts;

    private TimeSpan GetDelay(int attempt)
    {
        return TimeSpan.FromMilliseconds(
            UniformRandom(_initialDelay.TotalMilliseconds,
                Math.Pow(Exponent, attempt)));
    }

    private double UniformRandom(double a, double b)
    {
        if (a == b) return a;

        return a + (b - a) * _random.NextDouble();
    }
}