Code coverage on coveralls

I broke the construction of code coverage on tantivy and I am trying to bring it back.

What is the right way to get code coverage on coveralls nowadays?
Is tarpaulin ready for multithreaded code? Is travis-cargo working these days?

(Bonus point if you have a link for an example travis configuration)

Here's a link to one of my .travis.yml that's currently using cargo-travis to report to

Cargo travis also has support for coveralls, but I can't say I've used it.


Thanks you!