4.x
4.x: Java Migration; records, newer API, newer syntax (#8187)
4.x: Fix consumer retention in cache() upon subscribe-cancel race (#8283)
4.x: Cleanup, fix inferable types via var or diamond (#8189)
4.x: Cleanup: Serial annotation, getFirst usage (#8180)
4.x: Cleanup - Migration; lambdas expressions (#8188)
4.x: Fix Streamable.fromStream not closing the Stream (#8267)