Retry.cs

using System;
using System.ServiceModel;
using System.Threading;

public class Retry
{
    private const int RateLimitExceededErrorCode = -2147015902;
    private const int TimeLimitExceededErrorCode = -2147015903;
    private const int ConcurrencyLimitExceededErrorCode = -2147015898;

    public static TResult Do<TResult>(Func<TResult> func, int maxRetries = 3)
    {
        int retryCount = 0;

        while (true)
        {
            try
            {
                return func();
            }
            catch (FaultException<Microsoft.Xrm.Sdk.OrganizationServiceFault> ex)
                when (IsTransientError(ex))
            {
                if (++retryCount >= maxRetries)
                {
                    throw;
                }

                if (ex.Detail.ErrorCode == RateLimitExceededErrorCode)
                {
                    // Use Retry-After delay when specified
                    delay = (TimeSpan)ex.Detail.ErrorDetails["Retry-After"];
                }
                else
                {
                    // else use exponential backoff delay
                    delay = TimeSpan.FromSeconds(Math.Pow(2, retryCount));
                }

                Thread.Sleep(delay);
            }
        }
    }

    private static bool IsTransientError(FaultException<Microsoft.Xrm.Sdk.OrganizationServiceFault> ex)
    {
        // You can add more transient fault codes to retry here
        if (ex.Detail.ErrorCode == RateLimitExceededErrorCode ||
            ex.Detail.ErrorCode == TimeLimitExceededErrorCode ||
            ex.Detail.ErrorCode == ConcurrencyLimitExceededErrorCode)
        {
            return true;
        }

        return false;
    }
}