+/* A "dynamic string", that is, a buffer that can be used to construct a
+ * string across a series of operations that extend or modify it.
+ *
+ * The 'string' member does not always point to a null-terminated string.
+ * Initially it is NULL, and even when it is nonnull, some operations do not
+ * ensure that it is null-terminated. Use ds_cstr() to ensure that memory is
+ * allocated for the string and that it is null-terminated. */