+/* Returns table schema 'ts' serialized into JSON.
+ *
+ * The "isRoot" member is included in the JSON only if its value would differ
+ * from 'default_is_root'. Ordinarily 'default_is_root' should be false,
+ * because ordinarily a table would be not be part of the root set if its
+ * "isRoot" member is omitted. However, garbage collection was not orginally
+ * included in OVSDB, so in older schemas that do not include any "isRoot"
+ * members, every table is implicitly part of the root set. To serialize such
+ * a schema in a way that can be read by older OVSDB tools, specify
+ * 'default_is_root' as true. */