I wanted to let you know that in the next few days we're going to check in a
change to the trunk that starts turning on our RSL usage by default. As
we've said, now that Flex 4 requires a Player that can handle the cached
framework libraries, we will be hosting libraries and having this feature
enabled by default. The way we'll do this during normal time in the trunk
is that if you were to run right out of your source (without really
building) we will probably run with the framework linked into your SWF. If
you use an actual build (nightly for example), we'll use a debug RSL that
doesn't get cached in the Player. Only when we're approaching final builds
will we have a signed SWZ for testing purposes (and that would be for
release builds that you set up; for debug builds we expect folks will use
the debug RSLs). You should be able to step into debug RSLs without a
problem, so we hope this will end up working for folks.
Not sure exactly when this will land, but if you see some swf sizes changing
when you're building, now you know why!