• Remove dependency to atomicwrites #833 .Implemented by @fulmicoton upon suggestion and research from @asafigan).
• Migrated tantivy error from the now deprecated failure crate to thiserror #760. (@hirevo)
• API Change. Accessing the typed value off a Schema::Value now returns an Option instead of panicking if the type does not match.
• Large API Change in the Directory API. Tantivy used to assume that all files could be somehow memory mapped. After this change, Directory return a FileSlice that can be reduced and eventually read into an OwnedBytes object. Long and blocking io operation are still required by they do not span over the entire file.
• Added support for Brotli compression in the DocStore. (@ppodolsky)
• Added helper for building intersections and unions in BooleanQuery (@guilload)
• Bugfix in Query::explain
• Removed dependency on notify #924. Replaced with FileWatcher struct that polls meta file every 500ms in background thread. (@halvorboe @guilload)
• Added FilterCollector, which wraps another collector and filters docs using a predicate over a fast field (@barrotsteindev)
• Simplified the encoding of the skip reader struct. BlockWAND max tf is now encoded over a single byte. (@fulmicoton)
• FilterCollector now supports all Fast Field value types (@barrotsteindev)
• FastField are not all loaded when opening the segment reader. (@fulmicoton)

This version breaks compatibility and requires users to reindex everything.