pub fn get_properties(&self) -> Result<&HashTable> {
        unsafe {
            self.handlers()?
                .get_properties
                .and_then(|props| props(self.mut_ptr()).as_ref())
                .ok_or(Error::InvalidScope)
        }
    }
Attempts to retrieve the properties of the object. Returned inside a
Zend Hashtable.

# Errors

* `Error::InvalidScope` - If the object handlers or the properties
cannot be retrieved.
src/types/object.rs