Nio based handlers

Hello all.
Got this today:

readpartial only works with Nio based handlers

question 1: is this worthy of reporting as a jira?
question 2: how do I use an nio based handler, instead of my current
open(‘filename’, ‘r’) ?

question 3: could the error message perhaps have a link to somewhere
describing what to do in more detail?

Thanks for reading.
-r