WIP multi sessions

WIP multi sessions

@router.get("/concurrent-queries")
async def parallel_select():
    async with db(multi_sessions=True):
        async def execute_query(query):
            return await db.session.execute(text(query))

        tasks = [
            asyncio.create_task(execute_query("SELECT 1")),
            asyncio.create_task(execute_query("SELECT 2")),
            asyncio.create_task(execute_query("SELECT 3")),
            asyncio.create_task(execute_query("SELECT 4")),
            asyncio.create_task(execute_query("SELECT 5")),
            asyncio.create_task(execute_query("SELECT 6")),
        ]

        await asyncio.gather(*tasks)