Is synchronization required when simultaneously updating a variable with hundreds of coroutines running on Dispatchers.Main?

If all coroutines are launched on Dispatchers.Main, they execute on the same thread — the main UI thread of Android. In this case, concurrent parallel access to a variable does not occur, as the code executes sequentially on a single thread.

Therefore, synchronization when updating a variable from coroutines on Dispatchers.Main is usually not required. However, if the variable can be modified from other threads, then synchronization is necessary.

Example: if you have 100 coroutines on Dispatchers.Main, they will execute sequentially, and data races will not occur.