void removeValueChangedCallback(@Nullable final Object attribute) {
		synchronized (valueChangedCallbacks) {
			final ValueChangedCallback callback = valueChangedCallbacks.remove(attribute);
			if (callback != null) {
				callback.notifyClosed();
			}
		}
	}
Removes the callback set using {@link #getValueChangedCallback(Object)}.

@param attribute attribute to unbind the callback from.
ble/src/main/java/no/nordicsemi/android/ble/BleManagerHandler.java