React DOM

• Fix edge case where a hook update wasn't being memoized. (@sebmarkbage in #16359)
• Fix heuristic for determining when to hydrate, so we don't incorrectly hydrate during an update. (@sebmarkbage in #16739)
• Clear additional fiber fields during unmount to save memory. (@trueadm in #16807)
• Fix bug with required text fields in Firefox. (@halvves in #16578)
• Prefer Object.is instead of inline polyfill, when available. (@ku8ar in #16212)
• Fix bug when mixing Suspense and error handling. (@acdlite in #16801)

Scheduler (Experimental)

• Improve queue performance by switching its internal data structure to a min binary heap. (@acdlite in #16245)
• Use postMessage loop with short intervals instead of attempting to align to frame boundaries with requestAnimationFrame. (@acdlite in #16214)

useSubscription

• Avoid tearing issue when a mutation happens and the previous update is still in progress. (@bvaughn in #16623)

Artifacts

• react: https://unpkg.com/react@16.10.0/umd/ • react-art: https://unpkg.com/react-art@16.10.0/umd/ • react-dom: https://unpkg.com/react-dom@16.10.0/umd/ • react-is: https://unpkg.com/react-is@16.10.0/umd/ • react-test-renderer: https://unpkg.com/react-test-renderer@16.10.0/umd/ • scheduler: https://unpkg.com/scheduler@0.16.0/umd/