+ /**
+ * Appends sample data for a single channel where each byte
+ * represents one sample - if it's 0 the state is low, if 1 high.
+ * Other values are not permitted.
+ * Assumes that all channels are having samples added and in the
+ * order of 0..n, not n..0.
+ * Also assumes the the number of samples added for each channel
+ * is constant for every invokation for 0..n. The number of samples
+ * hence may only change when index is 0.
+ */
+ void append_subsignal_payload(unsigned int index, void *data,
+ uint64_t data_size, vector<uint8_t>& destination);
+