A factory which generates
Invoker instances that are optimized for
32 bit integer and float parameters / result types with 3 or less parameters.
Technical background: Instead of trying to cram all calls down a generic call
path, then figuring out how to convert the parameters in the native code on
each call, jffi supplies arity and type specific call paths that can be
optimized ahead of time by the native code.
The downside of this approach is more java code to wire up the functions and
call them using the arity+type specific paths, but in the case of int and float
parameters, it can result in more than a 100% speed boost over the generic path.