Don't use key.set_key on Ruby 2.3, it is not always available on this version. (#3)
Don't use key.set_key on Ruby 2.3, it is not always available on this version. (#3)

Compatibility with Ruby 2.3 was broken in commit
09632231b7653f47c3d176aa99bc1baf6009d396 (a fix for 2.4).

See https://github.com/tootsuite/mastodon/issues/2029 .
Gargron/ostatus2