I’m working on a Android project using coroutines and I have a sequence of operations that involve both IO-bound and CPU-bound tasks. Here’s what my process looks like:

1. Fetch data from the network (IO-bound).
2. Parse the fetched data (CPU-bound).
3. Save the parsed data to a database (IO-bound).
4. Retrieve the saved data from the database (IO-bound).

Initially, I planned to execute the entire process inside a withContext(Dispatcher.IO) block. However, I’m uncertain if this is the best approach, particularly for the parsing step, which is CPU-intensive.

Here’s a simplified version of my current code:

viewModelScope.launch {
    withContext(Dispatcher.IO) {
        // Step 1: Get data from the network (IO-bound)
        val data = fetchDataFromNetwork()

        // Step 2: Parse the data (CPU-bound)
        val parsedData = parseData(data)

        // Step 3: Save parsed data to the database (IO-bound)
        saveDataToDatabase(parsedData)

        // Step 4: Retrieve data from the database (IO-bound)
        val retrievedData = getDataFromDatabase()

        // Step 5: Use the retrieved data
        useRetrievedData(retrievedData)
    }
} 

I’ve read that CPU-intensive tasks should be executed on Dispatcher.Default to avoid blocking IO threads, but I’m not entirely sure if it’s necessary in this case. My questions are:

What exactly qualifies as a CPU-intensive task in the context of coroutines?
Would parsing data be considered a CPU-intensive task?
Should I move the parsing step to Dispatcher.Default, and if so, what would be the optimal way to structure my coroutine?

My intention was to use to execute a use case under one Dispacter.IO

suspend fun <T : UseCase.RequestValue, R> executeNow(useCase: UseCase<T, R>, values: T): Result<R>
{
    useCase.requestValues = values

    return withContext(Dispatchers.IO) {
        useCase.run()
    }
}

Now the usecase would be running inside a IO thread, and inside the usecase when the repository got the value from network, should I switch inside the IO thread to an Default thread for parsing, the retrieved data to object my model? Or is optimal to do the work in IO thread itself?