Azure StorageAccount ClobBlob leases - useful as semaphores for ensuring e.g. only on job is processing a given queue at a time

AzureStorageCloudBlobLease.cs

public class AzureStorageCloudBlobLease
{
    private readonly CloudBlob blob;
    private string leaseId;

    public AzureStorageCloudBlobLease(CloudBlob blob)
    {
        this.blob = blob ?? throw new ArgumentNullException(nameof(blob));
    }

    public async Task AcquireAsync(TimeSpan leaseTime, TimeSpan maxWaitingTimeForLease)
    {
        var startTime = DateTime.UtcNow;
        while (true)
        {
            var timedOut = DateTime.UtcNow > startTime.Add(maxWaitingTimeForLease);
            try
            {
                leaseId = await blob.AcquireLeaseAsync(leaseTime, Guid.NewGuid().ToString());
                break;
            }
            catch (StorageException sex) when (sex.RequestInformation.HttpStatusCode == (int)HttpStatusCode.Conflict)
            {
                if (!timedOut)
                {
                    // Randomize the waking up times a bit for heijunka (平準化) (load-levelling)
                    Thread.Sleep(TimeSpan.FromMilliseconds(750 + new System.Random().Next(500)));
                }
                else
                {
                    throw new ApplicationException("Could not acquire lease", sex);
                }
            }
        }
    }

    public async Task RenewAsync()
    {
        AssertLeaseAcquired();
        await blob.RenewLeaseAsync(AccessCondition.GenerateLeaseCondition(this.leaseId));
    }

    private void AssertLeaseAcquired()
    {
        if (leaseId is null) throw new InvalidOperationException("Lease not acquired");
    }

    public async Task ReleaseAsync()
    {
        if (leaseId is null) throw new InvalidOperationException("Lease not acquired");
        await this.blob.ReleaseLeaseAsync(AccessCondition.GenerateLeaseCondition(this.leaseId));
    }
}