First commit, step 4 completed

docs/annotations/Annotations/Core/Libraries/CallbackHandler-1.0/CallbackHandler-1.0.lua

@@ -0,0 +1,27 @@
+---@meta _
+
+-- ----------------------------------------------------------------------------
+-- CallbackHandler-1.0
+-- ----------------------------------------------------------------------------
+---@class CallbackHandler-1.0
+local CallbackHandler = {}
+
+---@param target table target object to embed public APIs in
+---@param RegisterName? string name of the callback registration API, default "RegisterCallback"
+---@param UnregisterName? string name of the callback unregistration API, default "UnregisterCallback"
+---@param UnregisterAllName? string name of the API to unregister all callbacks, default "UnregisterAllCallbacks". false == don't publish this API.
+---@return CallbackHandlerRegistry
+function CallbackHandler:New(target, RegisterName, UnregisterName, UnregisterAllName) end
+
+-- ----------------------------------------------------------------------------
+-- CallbackHandlerRegistry
+-- ----------------------------------------------------------------------------
+---@class CallbackHandlerRegistry
+---@field OnUnused? fun(registry: CallbackHandlerRegistry, target: table, eventName: string) If defined, called when an event stops.
+---@field OnUsed? fun(registry: CallbackHandlerRegistry, target: table, eventName: string) If defined, called when an event starts.
+local CallbackHandlerRegistry = {}
+
+---fires the given event/message into the registry
+---@param eventname string
+---@param ... unknown passed to the functions listening to the event.
+function CallbackHandlerRegistry:Fire(eventname, ...) end