Lock up of implemented UI.

[rndthoughts]

Describe the bug

I have implemented pjsip4net in a WinForms (4.7.1) application and use the .Build.Start() function to start pjsip from Program.cs. Everything works correctly except I keep getting regular but intermittent UI lockups. I initially thought it would be because there are locks around procedures like "GetCallById" and multiple calls might be deadlocking the UI but i've removed all these and it still happens. I've also run a profiler on the code and I can't see any deadlocks occurring.

It doesn't appear to be a call state change, as it usually happens mid-call. The call is not dropped and the user's can still hear each other. I have no errors logged and nothing in the trace logs. The whole UI just freezes. I think pjsip is being hosted in the main UI thread but I'm not sure why this would lock the UI. Is there a way i can move it to another thread?

To Reproduce Steps to reproduce the behavior:

1. Answer/Make a Call
2. UI locks up mid-call

Expected behavior UI should stay responsive

Screenshots N/A Environment (please complete the following information):

• OS: Windows 10
• Ethernet
• Version - Latest

App configuration (please complete the following information):

• Either an xml config: [e.g. App.config]
• or a code config: [e.g. custom IConfigurationProvider, fluent config]

Additional context Add any other context about the problem here.

[siniypin]

Hi Steve,

as a rule of thumb you should run your SIP UserAgent in a background thread and update your UI through a SynchronizationContext making no downstream calls to pjsip4net in callbacks you'd dispatch.

Cheers

[siniypin]

I've concluded that it is a decision app developers supposed to make on their own, whether to dispatch events to any SyncCtx present.

[siniypin]

Here, found some old samples: https://gist.github.com/siniypin/5f403be8dc6e5b2f802e926c1b7855d3

[rndthoughts]

Thanks, I'll take a look!

[siniypin]

Hi Steve,

did it work for you? Care to share your findings?