Release v19.63.0

Added

• [ReactorSideEffect] marks a type as a reactor side-effect return type, so analyzer CHR0054 accepts reactor handlers that return it synchronously, or return an array or IEnumerable<T> of it. Hosts that register an IReactorSideEffectHandler for their own return types, such as Arc's command invocations, put it on those types. The marker only informs the analyzer; a registered handler still processes the value. See CHR0054 (#4882)

Fixed

• The CHR0054 reference and the reactor side-effects documentation no longer say that a synchronous custom side-effect type cannot be used: the runtime accepts it when a registered handler claims the type (#4882)