Adds the specified string to a string table, which will cache it and network it to all clients automatically.
Whenever you want to create a net message with net.Start, you must add the name of that message as a networked string via this function.
If the passed string already exists, nothing will happen and the ID of the existing item will be returned.
The string table used for this function does not interfere with the engine string tables and has 4095 slots.
This limit is shared among all entities, SetNW* and SetGlobal* functions. If you exceed the limit, you cannot create new variables, and you will get the following warning: