Optimize product loading time

[alexshikov]

⬅️ As Is

• Product loading takes a while (3-4 seconds), due to sequential API requests

➡️ To Be

• Parallel possible API requests to reduce loading time
• Product loading time is within 2 seconds now
• Introduced first usage of async coroutines

☑️ Checklist

• Useless comments and/or Log.d etc are removed
• Unit test are covered
• Code has been deployed and tested on STG
• ClickUp ticket status has been updated to production
• Update CHANGELOG.md with the new changes

[akueisara]

https://stackoverflow.com/questions/59368838/difference-between-coroutinescope-and-coroutinescope-in-kotlin
For calling async, you can create a coroutine scope as follows:

internal suspend fun fetchInitialData(
        language: VirtusizeLanguage?,
        product: VirtusizeProduct,
    ) = coroutineScope {
    // optional: It doesn't return a Job instead of Deferred although it inherits from Job. 
    // It might be better to remove the job naming
    val storeProduct = async {
        virtusizeAPIService.getStoreProduct(productId)
    }

    storeProduct.await()
    ...
}

[alexshikov]

Often we need to use the result of await() which is technically a desirable object:

val storeProductJob = async {
    virtusizeAPIService.getStoreProduct(productId)
}

val storeProduct = storeProductJob.await()

Would using another prefix, like storeProductDeferred or storeProductAsync be a better option?

[alexshikov]

Coroutine scope created. Still keep the naming though. Let me know if you have a better naming or approach to use result of .await().

[akueisara]

I would think storeProductDeferred or storeProductAsync sounds better, but it's up to you.

[alexshikov]

@akueisara fyi, because linter breaks the formatting of the whole productCheck function, I've decided to refactor it a bit by reducing nesting. Sorry for including this in the same PR, but the linter mess the code anyway.