go-deadlock | Online deadlock detection in go

I'm trying to implement graceful channel closing from receiver side.

Yes, I'm aware that this violates the channel closing rule:

...don't close a channel from the receiver side and don't close a channel if the channel has multiple concurrent senders.

But I want to implement such logic. Unfortunately, I fail into deadlock issue in the number of cases: the application just hangs for the unlimited time, trying to lock same locked Mutex again.

So, I have 2 goroutines:

• one that will write into a channel and
• another that will receive data + will close channel from the receiver side.

My channel wrapped in the struct with sync.Mutex and closed boolean flag: