This is in fact the third catagory of select(), "exceptional conditions", but because some find the term "exceptional" confusing when used in a Python module, we decided to use the term "urgent data", borrowed from the poll(2) man page. (see bpo-30844)

An example of an exceptional conditions event is "out of band", another one is edge detection from GPIO Sysfs Interface.

The patch for fulfilling this issue can and will be supplied if and when bpo-30844 is merged. 30844 originally also contained the patch to asyncio, but I was asked to split it into two separate patches.