The unevaluated arguments to prepend to the calls to the getter and setter functions (usually item/key etc)
The name of the native function implementing the get functionality (will be called with the startArgs)
The name of the native function implementing the set functionality (will be called with the startArgs plus the value to set to)
The env that the startArgs should be evaluated in
Return a reference, which can be used as a value like normal, but also assigned to to change its value.