+ /*
+ * This is guaranteed by allocating with zalloc_or_die()
+ * and never (intentionally) writing to the last byte.
+ *
+ * receive_buffer_size is the size of the part of the
+ * buffer we intentionally write to, but we actually
+ * allocated receive_buffer_size+1 bytes so the assertion
+ * stays within the allocated range.
+ */
+ assert(receive_buffer[receive_buffer_size] == '\0');
+