listen_it Expert - ValueListenable Operators & Reactive Collections

What: Extension methods on ValueListenable/Listenable for transformations, filtering, debouncing. Plus reactive collections. Pure Dart.

CRITICAL RULES

• Operators return NEW ValueListenable objects - MUST capture the result
• listen() signature differs: on Listenable gets (subscription), on ValueListenable gets (value, subscription)
• mergeWith() is an INSTANCE method on ValueListenable, NOT a static method
• There is NO throttle() operator
• NEVER create operator chains inline in build() - memory leak! Use class fields or watch_it
• All operators support {bool lazy = false} for deferred initialization

listen() - Subscribing to Changes