```
[] ~/projects/jruby/hutch $ rvm ruby-2.5.3 do ruby -e 'class IO; m = instance_method(:write); p m.parameters; define_method(:write, m); end; $stderr.puts IO.instance_method(:write).parameters'
[[:rest]]
rest

[] ~/projects/jruby/hutch $ jruby -e 'class IO; m = instance_method(:write); p m.parameters; define_method(:write, m); end; $stderr.puts IO.instance_method(:write).parameters'
[[:req]]
req
```