v0.20.0

What's Changed

• Update Rust crate tokio to 1.15 by @renovate in #74
• Fixed displaying errror messages by @abdolence in #78
• auth.test implementation by @abdolence in #79
• Tokio/Hyper threading/locks optimizations by @abdolence in #80

Thanks for findings and help with the changes to @da-x

Socket Mode Internal API changes

Socket Mode internal API affected in this release since clients management implementation relocated to Tokio/Hyper module.

Full Changelog: v0.19.0...v0.20.0