v0.21.1.alpha1
Pre-release
      Pre-release
    
        (not released to RubyGems, just GH release)
- [Enhancement] Replace TTL-based partition count cache with a global cache that reuses 
librdkafkastatistics data when possible. - [Enhancement] Support producing and consuming of headers with mulitple values (KIP-82).
 - [Enhancement] Allow native Kafka customization poll time.
 - [Enhancement] Roll out experimental jruby support.
 - [Fix] Fix issue where post-closed producer C topics refs would not be cleaned.
 - [Fix] Fiber causes Segmentation Fault.
 - [Change] Move to trusted-publishers and remove signing since no longer needed.