presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/SemiTransactionalHiveMetastore.java/SemiTransactionalHiveMetastore/grantRoles
class SemiTransactionalHiveMetastore:    public synchronized void grantRoles(Set<String> roles, Set<HivePrincipal> grantees, boolean withAdminOption, HivePrincipal grantor)
    {
        setExclusive((delegate, hdfsEnvironment) -> delegate.grantRoles(roles, grantees, withAdminOption, grantor));
    }