A new step, wait-for-android-emulator(0.9.0) just released!
Now you can start an Android emulator using start-android-emulator step, and wait for it to boot in separated steps.
This way you can save time for your complete workflow! For example if you start an Android emulator in the first couple of positions of your workflow, you can do a lot of other jobs while it boots, and before you need to use the emulator you can use this step to validate if the emulator is running and ready, or if not, it waits for it. (But definitely you’ll need to wait less than before 
)
How-to use this new feature?
How to guide:
http://discuss.bitrise.io/t/how-to-speed-up-android-emulator-heavy-workflows