redis driver _get_lock set lock_key problem

Hi,

i went deeper and deeper into the redis driver handling (in CI 3.1.6.).
Why is it necessary to acquire a lock on read (Line 171 in libraries/Session/drivers/Session_redis_driver.php)?
In my opinion this line of code produces 99 % of all redis errors because the session is locked from the beginning of the first read until at least a session_write_close() call... -> locks are only needed for writing purposes, am i right?

Thank you