sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession);
By default, this function always returns 0. For it to return a useful result, the sqlite3_session object must have been configured to enable this API using sqlite3session_object_config() with the SQLITE_SESSION_OBJCONFIG_SIZE verb.
When enabled, this function returns an upper limit, in bytes, for the size of the changeset that might be produced if sqlite3session_changeset() were called. The final changeset size might be equal to or smaller than the size in bytes returned by this function.
See also lists of Objects, Constants, and Functions.
SQLite is in the Public Domain.
https://sqlite.org/session/sqlite3session_changeset_size.html