AlliedModders - How to use entity state inside AddToFullPack?

I am trying to set an entity visible to certain players. Upon creation of the entity, I set its rendermode to kRenderTransTexture and amount to 0, making them invisible globally, and it works.
Now, in AddToFullPack, I am exchanging information with certain clients and want to set the render properties to visible for them only.
I am not allowed to access any property as it gives me an error "Pointer to incomplete class type is not allowed". What's the deal here? I don't want to make the entity visible globally, just for certain players.

Code:

int AddToFullPack(struct entity_state_s* state, int e, edict_t* ent, edict_t* host, int hostflags, int player, unsigned char* pSet) {



    // Check for specified entity

    // Check if player is valid and meets conditions to make entity visible for.



    // If requirements are met, change the entity's rendermode and amount...

    state->rendermode = kRenderTransTexture;

    state->renderamt = 255;



    // ^

    // Those two lines are giving me the error. What am I to do with state?



    return 1;

}