MvvmCross ensures that messages are not lost when using `SubscribeOnThreadPoolThread` by implementing a queuing mechanism. When you subscribe to messages using `SubscribeOnThreadPoolThread`, any incoming messages are queued for asynchronous processing on a thread pool thread. This approach guarantees that messages are processed in the order they are received, even if the message publisher and the subscriber are on different threads.
Here's a detailed explanation of how this works:
1. Message Queueing: When a message is published and there are subscribers using `SubscribeOnThreadPoolThread`, the message is added to a queue. This ensures that messages are not lost, even if the subscriber is not immediately available to process them.
2. Thread Pool Processing: The queued messages are then processed asynchronously by a thread pool thread. This means that messages are handled in a non-blocking manner, preventing the UI or the publisher from being delayed.
3. Order of Processing: Messages are processed in the order they were received. This ensures that the order of events is preserved, which is crucial for maintaining the integrity of the application's state.
4. Weak References: By default, MvvmCross uses weak references for subscriptions, which helps prevent memory leaks. However, when using `SubscribeOnThreadPoolThread`, it's essential to ensure that the subscription token is stored properly to prevent the subscription from being garbage collected prematurely.
5. Subscription Tokens: When subscribing, a token is returned, which must be stored by the subscriber. This token can be used to unsubscribe from the message type later. Storing the token ensures that the subscription remains active until explicitly unsubscribed.
In summary, MvvmCross ensures that messages are not lost when using `SubscribeOnThreadPoolThread` by queuing messages for asynchronous processing on a thread pool thread, maintaining the order of processing, and using subscription tokens to manage subscriptions effectively. This approach allows for efficient and reliable message handling across different threads in an application.
Citations:[1] https://www.mvvmcross.com/documentation/plugins/messenger
[2] https://stackoverflow.com/questions/17324650/mvvmcross-multithreading-ins
[3] https://www.mvvmcross.com/documentation/fundamentals/data-binding
[4] https://www.youtube.com/watch?v=HQdvrWWzkIk
[5] https://www.mvvmcross.com/documentation/advanced/customizing-using-App-and-Setup
[6] https://stackoverflow.com/questions/17602137/mvvmcross-how-does-this-view-get-linked-to-the-viewmodel/17602246
[7] https://www.mvvmcross.com/documentation/fundamentals/viewmodel-lifecycle
[8] https://diglib.tugraz.at/download.php?id=576a78335451d&location=browse
[9] https://stackoverflow.com/questions/37168519/alert-dialog-in-viewmodel-mvvmcross