Merge "Add a new module-only API to preload HttpEngine" into main am: c3a2764012

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3370478

Change-Id: I35b71cadb8759be631bf3d814660184c835196b3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>