Delta updates

[cbenhagen]

Please consider different methods to reduce the download size.

Without access to all old APKs:

• zsync
• zsync2
• hsynz

Versioned patches:

• archive-patcher
• ApkDiffPatch

[MartinHlavna]

Hello,
thanks for the idea. We are not currently considering this, but if you can provide well written PR, we will be happey to merge.

[MartinHlavna]

This may be potentially done in new PackageInstaller method. We are currently doing only full install but it may not be far away from supporting deltas if anyone wants to look into this.