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WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000
00:00:00.506 --> 00:00:10.416 A:middle
[Silence]
00:00:10.916 --> 00:00:12.066 A:middle
>> Nick Colet: My name is
Nick Colet [assumed spelling]
00:00:12.856 --> 00:00:14.716 A:middle
[applause] I'm a
[laughter] -- thank you.
00:00:17.296 --> 00:00:20.426 A:middle
I'm a software engineer on the
Core Data team here at Apple,
00:00:20.426 --> 00:00:24.086 A:middle
and I'm excited to take you
through what's new in Core Data
00:00:24.586 --> 00:00:26.886 A:middle
in iOS 7 and Mac OS X 10.9.
00:00:28.356 --> 00:00:29.676 A:middle
We've done a lot of great work
00:00:29.676 --> 00:00:31.676 A:middle
in the Core Data framework
over the last year.
00:00:32.686 --> 00:00:35.616 A:middle
We've made a significant number
of improvements to key areas
00:00:35.616 --> 00:00:39.316 A:middle
to improve performance,
reliability and stability,
00:00:39.996 --> 00:00:42.986 A:middle
but today, we want to take a
moment to focus on just a few
00:00:42.986 --> 00:00:45.676 A:middle
of them, beginning with iCloud.
00:00:45.846 --> 00:00:47.596 A:middle
Now, we've made a
number of improvements
00:00:47.596 --> 00:00:48.826 A:middle
to our iCloud integration.
00:00:49.036 --> 00:00:51.276 A:middle
We've been iterating on
it for almost 12 months
00:00:51.276 --> 00:00:53.436 A:middle
since our WWDC session
last year,
00:00:54.016 --> 00:00:57.346 A:middle
and we took into account a lot
of your feedback that we've seen
00:00:57.346 --> 00:01:00.786 A:middle
on developer forums, in
radars and around the web.
WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000
00:00:57.346 --> 00:01:00.786 A:middle
on developer forums, in
radars and around the web.
00:01:01.606 --> 00:01:04.626 A:middle
And so, the improvements
that we've made require us
00:01:04.626 --> 00:01:07.546 A:middle
to revisit a few of the topics
that we discussed last year,
00:01:08.296 --> 00:01:10.346 A:middle
beginning with improvements
we've made
00:01:10.346 --> 00:01:14.116 A:middle
to the fallback store, as
well as changes to how you set
00:01:14.116 --> 00:01:18.246 A:middle
up the store asynchronously;
and what happens
00:01:18.246 --> 00:01:21.586 A:middle
with iCloud transition events
like when the account changes.
00:01:22.626 --> 00:01:25.076 A:middle
We're also going to
talk about some new API
00:01:25.116 --> 00:01:26.386 A:middle
that we're introducing today.
00:01:26.386 --> 00:01:30.316 A:middle
And finally, I'll
introduce you to some changes
00:01:30.316 --> 00:01:33.166 A:middle
that have happened across the
organization and developer tools
00:01:33.436 --> 00:01:36.846 A:middle
and frameworks to change how
you live and work on iCloud.
00:01:37.556 --> 00:01:38.826 A:middle
They'll make it easier to use
00:01:39.016 --> 00:01:40.806 A:middle
and provide a lot
more transparency
00:01:40.806 --> 00:01:42.336 A:middle
than was previously
available to you.
00:01:44.116 --> 00:01:46.036 A:middle
Then, Melissa Turner
will come up
00:01:46.036 --> 00:01:47.326 A:middle
and take you through some demos.
00:01:48.216 --> 00:01:51.276 A:middle
And finally, Ben Trumbull will
come up and give you an overview
00:01:51.536 --> 00:01:54.216 A:middle
of several enhancements that
we've made to the SQLite store.
00:01:55.406 --> 00:01:58.246 A:middle
Now, before I dive into
the meat of the discussion,
00:01:58.736 --> 00:02:01.826 A:middle
I'd like to take a moment
to frame it by talking
WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000
00:01:58.736 --> 00:02:01.826 A:middle
I'd like to take a moment
to frame it by talking
00:02:01.826 --> 00:02:04.476 A:middle
about our goals and
objectives related to iCloud.
00:02:05.146 --> 00:02:09.015 A:middle
You see, last year after iOS
6 and Mac OS X 10.8 shipped,
00:02:09.576 --> 00:02:11.796 A:middle
we took a look at our
iCloud integration and tried
00:02:11.796 --> 00:02:15.116 A:middle
to identify several key
areas where we could focus
00:02:15.116 --> 00:02:17.886 A:middle
on providing valuable
improvements toward integration,
00:02:18.536 --> 00:02:20.486 A:middle
the first of which is speed.
00:02:21.246 --> 00:02:23.576 A:middle
This year, we've made a
number of improvements
00:02:23.576 --> 00:02:26.106 A:middle
that will change not only how
efficient our integration is
00:02:26.106 --> 00:02:29.316 A:middle
in terms of its memory
usage, its processing usage
00:02:29.606 --> 00:02:33.086 A:middle
and battery consumption,
but also how well it deals
00:02:33.086 --> 00:02:34.406 A:middle
with iCloud under the hood.
00:02:34.866 --> 00:02:36.106 A:middle
We've made a number
of improvements
00:02:36.106 --> 00:02:39.056 A:middle
to downloading files so
that changes appear faster
00:02:39.426 --> 00:02:42.326 A:middle
and peers can communicate
their changes faster than ever.
00:02:43.726 --> 00:02:45.966 A:middle
We also strove to
improve simplicity.
00:02:46.696 --> 00:02:48.986 A:middle
You see, after we
shipped last year,
00:02:49.226 --> 00:02:51.906 A:middle
we felt the developers
still had to write a number
00:02:51.936 --> 00:02:55.726 A:middle
of complex pieces of code
to integrate successfully
00:02:55.726 --> 00:02:58.246 A:middle
with our iCloud integration
and we found
00:02:58.246 --> 00:03:01.656 A:middle
that this hampered your ability
to build effective applications
WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000
00:02:58.246 --> 00:03:01.656 A:middle
that this hampered your ability
to build effective applications
00:03:01.996 --> 00:03:03.706 A:middle
that worked on top
of our integration.
00:03:04.716 --> 00:03:08.036 A:middle
And finally, we really want
to focus on consistency.
00:03:08.606 --> 00:03:11.926 A:middle
As you may have noticed, we
didn't have a clear paradigm
00:03:11.926 --> 00:03:15.156 A:middle
that you could reuse over
and over again, when working
00:03:15.156 --> 00:03:18.336 A:middle
with our integration, and this
made it exceptionally difficult,
00:03:18.536 --> 00:03:20.966 A:middle
or at least more difficult
than we had originally planned
00:03:21.346 --> 00:03:24.296 A:middle
to handle transition events
like when the account changes.
00:03:24.566 --> 00:03:28.376 A:middle
So with that in mind, let's take
a look at the fallback store.
00:03:28.956 --> 00:03:32.756 A:middle
As you may remember, the
fallback store is a concept
00:03:32.756 --> 00:03:36.176 A:middle
that we introduced last
year at WWDC as a way
00:03:36.176 --> 00:03:38.246 A:middle
of providing a local
persistent store
00:03:38.346 --> 00:03:41.146 A:middle
that your application
could use in the event
00:03:41.146 --> 00:03:43.846 A:middle
that the iCloud store was
unavailable for a certain period
00:03:43.846 --> 00:03:47.386 A:middle
of time, and your application
would simply add the store
00:03:47.386 --> 00:03:49.496 A:middle
to the coordinator
to make it available
00:03:49.496 --> 00:03:51.096 A:middle
to your managed object context
00:03:51.276 --> 00:03:54.426 A:middle
so that your user could
write changes to disk while
00:03:54.426 --> 00:03:57.166 A:middle
in the background we set up
the iCloud store for you.
00:03:58.676 --> 00:04:00.986 A:middle
And this would produce
a pairing, if you will,
WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000
00:03:58.676 --> 00:04:00.986 A:middle
And this would produce
a pairing, if you will,
00:04:01.056 --> 00:04:03.226 A:middle
of a local persistent store file
00:04:03.226 --> 00:04:05.196 A:middle
and an iCloud persistent
store file
00:04:05.196 --> 00:04:07.196 A:middle
that were tied to
the same account.
00:04:08.276 --> 00:04:11.766 A:middle
Now, this worked out
rather well until,
00:04:12.946 --> 00:04:14.556 A:middle
you ended up with
multiple accounts,
00:04:15.536 --> 00:04:17.766 A:middle
and this is when things
became a bit cumbersome
00:04:18.245 --> 00:04:20.136 A:middle
because developers would
end up spending a lot
00:04:20.136 --> 00:04:21.736 A:middle
of their time writing codes
00:04:21.736 --> 00:04:24.896 A:middle
and manage these different
persistent store files instead
00:04:24.896 --> 00:04:26.886 A:middle
of focusing on building
our applications.
00:04:27.596 --> 00:04:30.686 A:middle
And so for iOS 7
and Mac OS X 10.9,
00:04:31.166 --> 00:04:33.096 A:middle
we've completely
eliminated the need for you
00:04:33.096 --> 00:04:34.456 A:middle
to manage the fallback store.
00:04:35.036 --> 00:04:36.866 A:middle
We've subsumed that
responsibility
00:04:36.866 --> 00:04:39.996 A:middle
into the framework and it
will be entirely managed
00:04:39.996 --> 00:04:40.746 A:middle
by Core Data.
00:04:42.096 --> 00:04:45.766 A:middle
This also means [applause]
[laughter] -- thank you.
00:04:46.986 --> 00:04:49.906 A:middle
This also means that your
application will only ever use
00:04:49.996 --> 00:04:51.956 A:middle
one persistent store
file per account.
00:04:52.956 --> 00:04:57.056 A:middle
Now, we say "per account"
because we still have
00:04:57.056 --> 00:04:59.706 A:middle
to provide a different
actual persistent store file
00:04:59.706 --> 00:05:02.186 A:middle
for each iCloud account
that's in use on a system,
WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000
00:04:59.706 --> 00:05:02.186 A:middle
for each iCloud account
that's in use on a system,
00:05:03.136 --> 00:05:04.806 A:middle
and this requires
that we change a bit
00:05:04.806 --> 00:05:06.536 A:middle
of our guidance from
previous years.
00:05:07.286 --> 00:05:09.846 A:middle
You see, we had previously
advised
00:05:10.126 --> 00:05:12.456 A:middle
that you could keep
the iCloud store inside
00:05:12.456 --> 00:05:15.236 A:middle
of the iCloud container
in a .nosync folder.
00:05:15.906 --> 00:05:17.766 A:middle
This had a rather
convenient advantage
00:05:18.006 --> 00:05:20.446 A:middle
of automatically deleting
the store file for you
00:05:20.696 --> 00:05:21.866 A:middle
when the account went away.
00:05:22.796 --> 00:05:25.896 A:middle
However, because we
now take responsibility
00:05:25.896 --> 00:05:27.456 A:middle
for managing the fallback store
00:05:27.816 --> 00:05:30.556 A:middle
and the fallback store must
exist in local storage,
00:05:31.106 --> 00:05:33.916 A:middle
we now require that you store
the persistent store file
00:05:33.916 --> 00:05:37.946 A:middle
somewhere in local storage,
usually the application sandbox.
00:05:38.236 --> 00:05:40.376 A:middle
However, if your
application isn't sandboxed,
00:05:40.646 --> 00:05:42.976 A:middle
you can keep it wherever you
normally keep your persistent
00:05:42.976 --> 00:05:43.726 A:middle
store files.
00:05:47.036 --> 00:05:51.306 A:middle
Additionally, and because this
is now being taken over entirely
00:05:51.306 --> 00:05:55.086 A:middle
by Core Data, we want to
provide a bit more transparency
00:05:55.186 --> 00:05:58.836 A:middle
than we used to about events
that are happening related
00:05:58.836 --> 00:06:01.596 A:middle
to the fallback store,
and for this reason,
WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000
00:05:58.836 --> 00:06:01.596 A:middle
to the fallback store,
and for this reason,
00:06:01.596 --> 00:06:03.606 A:middle
we'll log some new
events to console
00:06:03.606 --> 00:06:05.906 A:middle
so that you can see them
during your development.
00:06:06.796 --> 00:06:08.776 A:middle
You may be familiar with
our Core Data logging.
00:06:09.016 --> 00:06:11.896 A:middle
All of our messages start
with CoreData: Ubiquity:
00:06:11.896 --> 00:06:14.646 A:middle
and when we're using
the fallback store,
00:06:14.906 --> 00:06:16.786 A:middle
you'll see Using
Local Storage 1.
00:06:17.606 --> 00:06:20.406 A:middle
You'll see Using Local
Storage 0 if we've been able
00:06:20.406 --> 00:06:22.356 A:middle
to transition off
the fallback store
00:06:22.356 --> 00:06:24.636 A:middle
and your application is
fully connected to iCloud.
00:06:25.576 --> 00:06:27.926 A:middle
Now, it's important that you
understand the expectations
00:06:27.926 --> 00:06:30.236 A:middle
associated with each
of these log messages.
00:06:30.866 --> 00:06:34.616 A:middle
Using Local Storage 1 means
that changes that you make
00:06:34.616 --> 00:06:37.186 A:middle
to the persistent store
are being persisted vocally
00:06:37.986 --> 00:06:40.616 A:middle
and they won't be available
to other peers over iCloud
00:06:40.996 --> 00:06:43.576 A:middle
until you see Using
Local Storage 0.
00:06:44.186 --> 00:06:45.496 A:middle
This is when you can expect
00:06:45.496 --> 00:06:47.496 A:middle
to start seeing import
notifications.
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And when you should expect
seeing your changes uploaded
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and made available
to other peers.
00:06:53.066 --> 00:06:57.876 A:middle
So that's the fallback store,
and now I'd like to tell you
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about some of the changes
we've made to how you set
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up the store asynchronously.
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up the store asynchronously.
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You may be familiar
with this line of code.
00:07:05.426 --> 00:07:07.916 A:middle
It simply adds persistent
store to an instance
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of NSPersistentStoreCoordinator;
and when you call it,
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you expect to get a store
file back fairly quickly.
00:07:16.596 --> 00:07:19.886 A:middle
In most situations,
especially those without iCloud,
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we only have to do a
small amount of network --
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of local I/O to bring the
persistent store file up,
00:07:26.756 --> 00:07:28.236 A:middle
so it returns immediately.
00:07:29.136 --> 00:07:33.416 A:middle
However, when it is connected
to iCloud, we sometimes have
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to do a significant
amount of network I/O
00:07:35.966 --> 00:07:37.556 A:middle
to make sure the
persistent store is
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in a state that's consistent
and ready to be used
00:07:40.146 --> 00:07:44.746 A:middle
by your application, and in iOS
6, we did this synchronously.
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That meant that whenever you
called add persistent store
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and you didn't have a
persistent store file on disk,
00:07:51.506 --> 00:07:53.796 A:middle
we would go out to the
network and discover the state
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of the contents of
the iCloud container.
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In iOS 7 and Mac OS X 10.9,
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we no longer do this work
synchronously within the call
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to addPersistentStore,
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so addPersistentStore will
always return immediately.
00:08:09.156 --> 00:08:11.456 A:middle
And this is a huge
benefit to your application
00:08:11.686 --> 00:08:13.366 A:middle
because it eliminates
the need for you
00:08:13.366 --> 00:08:15.766 A:middle
to call addPersistentStore
on a background thread.
00:08:15.796 --> 00:08:17.686 A:middle
Now, have we done this?
00:08:18.336 --> 00:08:21.126 A:middle
Well, we've done it by
using the fallback store.
00:08:21.916 --> 00:08:24.966 A:middle
We will transparently pass
the fallback store back
00:08:24.966 --> 00:08:27.986 A:middle
to your application and so that
you can begin working with it
00:08:28.196 --> 00:08:30.876 A:middle
and your user can begin
making changes immediately.
00:08:32.736 --> 00:08:36.466 A:middle
But, because we manage the
fallback store now, we were able
00:08:36.466 --> 00:08:38.535 A:middle
to take the integration
one step further
00:08:38.696 --> 00:08:40.736 A:middle
than we felt developers
could on their own.
00:08:41.626 --> 00:08:44.346 A:middle
We now store individual
transaction records
00:08:44.346 --> 00:08:46.726 A:middle
for each change that's
made to the fallback store
00:08:47.376 --> 00:08:51.136 A:middle
and this has implications for
both performance and bandwidth.
00:08:51.746 --> 00:08:55.236 A:middle
You see, last year, if your
application took responsibility
00:08:55.236 --> 00:08:57.426 A:middle
for migrating contents
from the fallback store
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to the iCloud store after the
iCloud store was available,
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to the iCloud store after the
iCloud store was available,
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you would have to do a
lot of extra work to scope
00:09:04.116 --> 00:09:05.756 A:middle
that migration and ensure
00:09:05.756 --> 00:09:07.606 A:middle
that it didn't consume
too much memory
00:09:07.926 --> 00:09:09.336 A:middle
or bandwidth over the wire.
00:09:10.146 --> 00:09:12.566 A:middle
However, now because
we keep our record
00:09:12.566 --> 00:09:16.106 A:middle
of each individual transaction,
all that work is done for you.
00:09:16.956 --> 00:09:19.936 A:middle
And this means that once the
iCloud store is available,
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we can transport those changes
into the container immediately
00:09:23.946 --> 00:09:25.796 A:middle
and make them available
to other peers.
00:09:26.166 --> 00:09:28.696 A:middle
So there's no additional work
for you to do the migrate data
00:09:28.696 --> 00:09:30.756 A:middle
from the fallback store
to the iCloud store.
00:09:31.726 --> 00:09:35.106 A:middle
But we also wanted to give
you a better way to tie
00:09:35.106 --> 00:09:38.006 A:middle
in with this transition
and that requires
00:09:38.006 --> 00:09:39.466 A:middle
that we introduce some new API.
00:09:40.706 --> 00:09:43.276 A:middle
Today, we're introducing
NSPersistentStoreCoordinator
00:09:43.276 --> 00:09:47.236 A:middle
Storage Will Change notification
as a way that we can tell you
00:09:47.576 --> 00:09:50.606 A:middle
that an event has occurred where
we need to change the contents
00:09:50.606 --> 00:09:52.336 A:middle
of the persistent
store file on disk.
00:09:53.356 --> 00:09:55.976 A:middle
When you receive it,
you can optionally call
00:09:56.036 --> 00:09:59.196 A:middle
NSManagedObjectContext
save if there are changes
00:09:59.196 --> 00:10:01.706 A:middle
in your managed object context
that you wish to persist,
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in your managed object context
that you wish to persist,
00:10:02.286 --> 00:10:05.126 A:middle
and then you can call
NSManagedObjectContext reset
00:10:05.126 --> 00:10:09.706 A:middle
and prepare your
UI for new data.
00:10:10.876 --> 00:10:13.526 A:middle
When we get control back from
your notification observer,
00:10:13.916 --> 00:10:16.226 A:middle
we'll remove the store from
the coordinator for you
00:10:16.716 --> 00:10:19.186 A:middle
and then post
NSPersistentStoreCoordinator
00:10:19.186 --> 00:10:21.066 A:middle
Storage Did Change notification
00:10:21.436 --> 00:10:22.846 A:middle
when the store is
ready to come up.
00:10:23.726 --> 00:10:25.086 A:middle
Now, it's important
that you realize
00:10:25.156 --> 00:10:26.916 A:middle
that this transition
is very fast.
00:10:27.526 --> 00:10:30.466 A:middle
It's almost as fast as if
you called addPersistentStore
00:10:30.466 --> 00:10:34.046 A:middle
on a store file without iCloud
options, so you shouldn't expect
00:10:34.046 --> 00:10:35.736 A:middle
to notice any interruption
00:10:35.786 --> 00:10:37.726 A:middle
in what your user sees
in the application.
00:10:39.096 --> 00:10:41.066 A:middle
You can then start working
with the storage just
00:10:41.066 --> 00:10:44.306 A:middle
as you normally would, and call
NSManagedObjectContext save
00:10:44.726 --> 00:10:45.956 A:middle
to make changes to
the iCloud store.
00:10:46.086 --> 00:10:50.196 A:middle
Now, once you've
handle this transition,
00:10:50.816 --> 00:10:53.936 A:middle
your application will be
fully up and running on iCloud
00:10:53.936 --> 00:10:54.896 A:middle
and you can expect that at
00:10:54.896 --> 00:10:57.456 A:middle
that point changes will be
available to other peers.
00:10:58.686 --> 00:11:01.866 A:middle
Now, I need to mention that
this is a special case scenario.
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Now, I need to mention that
this is a special case scenario.
00:11:02.516 --> 00:11:04.686 A:middle
You will only see these
notifications during our
00:11:04.686 --> 00:11:06.146 A:middle
asynchronous setup process
00:11:06.656 --> 00:11:09.376 A:middle
if there is no persistent
store file on disk,
00:11:09.736 --> 00:11:11.846 A:middle
or there are has been a
change to the iCloud account
00:11:11.946 --> 00:11:14.836 A:middle
or the contents of the container
since we last launched.
00:11:15.776 --> 00:11:19.246 A:middle
Normally, you'll just start
seeing NSPersistentStore Did
00:11:19.246 --> 00:11:21.666 A:middle
Import Ubiquitous Content
Changes notification
00:11:22.056 --> 00:11:24.396 A:middle
which you can merge into
your managed object context
00:11:24.646 --> 00:11:26.986 A:middle
by using merged changes
from Context Did Save.
00:11:28.296 --> 00:11:30.956 A:middle
This is important to
realize because the goal
00:11:30.956 --> 00:11:33.906 A:middle
of our integration this year
for asynchronous setup was
00:11:33.906 --> 00:11:35.546 A:middle
to eliminate any work
that you had to do
00:11:35.546 --> 00:11:36.996 A:middle
by your application at all.
00:11:37.496 --> 00:11:41.516 A:middle
However, we're providing this
new transition paradigm as a way
00:11:41.516 --> 00:11:45.366 A:middle
of enabling you to have a
consistent implement once use
00:11:45.366 --> 00:11:47.706 A:middle
case that you only
have to pay attention
00:11:47.706 --> 00:11:49.056 A:middle
to for our integration.
00:11:49.636 --> 00:11:54.566 A:middle
And so with that, let's
take a look at changes
00:11:54.836 --> 00:11:57.456 A:middle
for how you handle changes