NullReference issue with BlobHttpHandler

Description

Exception in ASP.NET. This issue cannot be reproduced. Error handling has been added to catch and log this error.

Application: w3wp.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.NullReferenceException
at System.Web.HttpApplication+CallHandlerExecutionStep.OnAsyncHandlerCompletion(System.IAsyncResult)
at EPiServer.Web.BlobHttpHandler.DisposeOnCallback(System.IAsyncResult, System.AsyncCallback, System.IDisposable)
at EPiServer.Web.MediaHandlerBase.HandleCallBack(System.IAsyncResult, System.AsyncCallback)
at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.IO.Stream+ReadWriteTask.System.Threading.Tasks.ITaskCompletionAction.Invoke(System.Threading.Tasks.Task)
at System.Threading.Tasks.Task.FinishContinuations()
at System.Threading.Tasks.Task.Finish(Boolean)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(System.Threading.Tasks.Task ByRef)
at System.Threading.Tasks.Task.ExecuteEntry(Boolean)
at System.Threading.ThreadPoolWorkQueue.Dispatch()