@NonNull
	public Request done(@NonNull final SuccessCallback callback) {
		this.successCallback = callback;
		return this;
	}
Use to set a completion callback. The callback will be invoked when the operation has
finished successfully unless the request was executed synchronously, in which case this
callback will be ignored.

@param callback the callback.
@return The request.
ble/src/main/java/no/nordicsemi/android/ble/Request.java