Allow to skip function name guessing

[pawelpabich]

First of all. Thanks for a great library!

Not sure whether this is happening only in my case, but the "guessed" names of functions are worse than what the JS runtime provides. Would it be possible to add an option to skip the name guessing?

Current

findFunctionName function skipped

[pawelpabich]

Also, happy to come up with a PR if that helps.

[jean-emmanuel]

+1 :)