Static methods

@:native("GetExtraContentPackHasBeenInstalled")staticGetExtraContentPackHasBeenInstalled():Bool

@:native("GetIsLoadingScreenActive")staticgetIsLoadingScreenActive():Bool

@:native("HasCloudRequestsFinished")statichasCloudRequestsFinished(variable:Dynamic, unused:Dynamic):Bool

Sets the value of the specified variable to 0.
Always returns true.

@:native("IsDlcPresent")staticisDlcPresent(dlcHash:Int):Bool

Example:
DLC::IS_DLC_PRESENT($\mpbusiness2\);
($ = gethashkey)
bruteforce these:
0xB119F6D
0x96F02EE6

@:native("OnEnterMp")staticonEnterMp():Dynamic

This loads the GTA:O dlc map parts (high end garages, apartments).
Works in singleplayer.
In order to use GTA:O heist IPL's you have to call this native with the following params: SET_INSTANCE_PRIORITY_MODE(1);

@:native("OnEnterSp")staticonEnterSp():Dynamic

Unloads GROUP_MAP (GTAO/MP) DLC data and loads GROUP_MAP_SP DLC. Neither are loaded by default, 0888C3502DBBEEF5 is a cognate to this function and loads MP DLC (and unloads SP DLC by extension).
The original (and wrong) definition is below:
This unload the GTA:O DLC map parts (like high end garages/apartments).
Works in singleplayer.