I don't see this framework going anywhere. The repo owner is the sole contributor [0], and is singularly pre-occupied with benchmarks and GitHub stars. The owner's entitlement about copy-pasted code, use of the royal "we", quickness to close issues without discussion, and pattern of editing and deleting issue comments are also discouraging.
He is not the sole contributor, actually. He squashes master every once in a while to a single commit, which removes other authors. If you peruse the travis builds page[1] you can see commits by other people
"Discouraging" is the nicest hedge you could have used. There are a bunch of Go frameworks and libraries and whatnot for writing web servers, this one should be passed by very quickly.
[0] https://github.com/kataras/iris/graphs/contributors