Update core_storage.go

		query = `

		INSERT INTO storage (collection, key, user_id, value, version, read, write, create_time, update_time)

		SELECT $1, $2, $3, $4, $5, $6, $7, now(), now()

			WHERE NOT EXISTS(SELECT 1 FROM storage WHERE collection = $1 AND key = $2 AND user_id = $3) -- avoids ON CONFLICT hitting pre-existing object and immediately cancels insert

			WHERE NOT EXISTS(SELECT 1 FROM storage WHERE collection = $1 AND key = $2 AND user_id = $3) -- avoids ON CONFLICT hitting pre-existing object, and immediately cancels insert

		ON CONFLICT (collection, key, user_id) DO UPDATE

			SET version = excluded.version WHERE storage.version = excluded.version AND storage.read = excluded.read AND storage.write = excluded.write -- needed to return a row on concurrent write of same object

		RETURNING read, write, version, create_time, update_time`