Add useSuspending to ConnectionPool for better Kotlin support

The current implementation of .use method is based on CompletableFuture and is not Kotlin-friendly. Instead, I had to write my own implementation that looks more or less like this:

suspend fun <T, C : ConcreteConnection> ConnectionPool<C>.useSuspending(
    block: suspend (SuspendingConnection) -> T
): T {
    var exception: Throwable? = null
    val connection = take().await()
    try {
        return block(connection.asSuspending)
    } catch (e: Throwable) {
        exception = e
        throw e
    } finally {
        if (exception == null) {
            giveBack(connection).await()
        } else {
            try {
                giveBack(connection).await()
            } catch (closeException: Throwable) {
                exception.addSuppressed(closeException)
            }
        }
    }
}

However, unlike the already provided .use function, this implementation is not using configuration.executionContext. Not sure how much of a problem this is. At any rate, it would be nice to have a similar API available for Kotlin users.

P.S. I initially started with r2dbc interface for jasync, but the code ends up bloated with all of the “await” statements…

[oshai]

@ilya40umov any update on this? would you like to add a PR?

[oshai]

Yes, I am looking at it.