Function XPLMUnshareData 

pub unsafe extern "C" fn XPLMUnshareData(
    inDataName: *const c_char,
    inDataType: XPLMDataTypeID,
    inNotificationFunc: XPLMDataChanged_f,
    inNotificationRefcon: *mut c_void,
) -> c_int

XPLMUnshareData

This routine removes your notification function for shared data. Call it when done with the data to stop receiving change notifications. Arguments must match XPLMShareData. The actual memory will not necessarily be freed, since other plug-ins could be using it.