title: NullReferenceException from EWS Nuget
body: <p>I am using <code>Exchange.WebServices.Managed.Api 2.2.1.2</code> Nuget package to send email from EWS 2016.
  Sometimes I am getting exception given below. Email is sent out and saved to Sent Items folder as well, so looks like this is not a server issue and seems like somehow Nuget package is throwing this misleading error.</p>
  <p>Has anyone encountered this?</p>
  <pre><code>    System.NullReferenceException: Object reference not set to an instance of an object.
     at Microsoft.Exchange.WebServices.Data.ServiceRequestBase.WrapStream(Stream responseStream, String contentEncoding)
     at Microsoft.Exchange.WebServices.Data.ServiceRequestBase.GetResponseStream(IEwsHttpWebResponse response)
     at Microsoft.Exchange.WebServices.Data.SimpleServiceRequestBase.ReadResponse(IEwsHttpWebResponse response)
     at Microsoft.Exchange.WebServices.Data.SimpleServiceRequestBase.InternalExecute()
     at Microsoft.Exchange.WebServices.Data.MultiResponseServiceRequest`1.Execute()
     at Microsoft.Exchange.WebServices.Data.ExchangeService.InternalCreateItems(IEnumerable`1 items, FolderId parentFolderId, Nullable`1 messageDisposition, Nullable`1 sendInvitationsMode, ServiceErrorHandling errorHandling)
     at Microsoft.Exchange.WebServices.Data.ExchangeService.CreateItem(Item item, FolderId parentFolderId, Nullable`1 messageDisposition, Nullable`1 sendInvitationsMode)
     at Microsoft.Exchange.WebServices.Data.Item.InternalCreate(FolderId parentFolderId, Nullable`1 messageDisposition, Nullable`1 sendInvitationsMode)
     at Microsoft.Exchange.WebServices.Data.EmailMessage.InternalSend(FolderId parentFolderId, MessageDisposition messageDisposition)
     at Microsoft.Exchange.WebServices.Data.EmailMessage.SendAndSaveCopy(WellKnownFolderName destinationFolderName)
     at Elliott.CollateralMgmt.Common.Email.Emailer.SendEws(Email email, Boolean isHtml, Dictionary`2 attachments) in /app/Elliott.CollateralMgmt.Common/Email/Emailer.cs:line 162
  </code></pre>