- A new series of :class:`.Session` methods which provide hooks

- A new series of :class:`.Session` methods which provide hooks
directly into the unit of work's facility for emitting INSERT
and UPDATE statements has been created.  When used correctly,
this expert-oriented system can allow ORM-mappings to be used
to generate bulk insert and update statements batched into
executemany groups, allowing the statements to proceed at
speeds that rival direct use of the Core.
fixes #3100