Investigate render flush at SkeletalMeshComponent InitLODInfos

From UDN :

we are spawning a number of characters at the same time during the game, and seeing a major framerate hitch when we do so. After the characters have been spawned, we use SetSkinnedAssetAndUpdate on their skeletal mesh components to configure them, which is part of what is taking the time. Among other things, it causes a render pipeline flush in USkinnedMeshComponent::InitLODInfos(), which means that spreading out the calculations over several frames is not as attractive, since that would give us about 35 frames in sequence with a render pipeline flush in them.

Is there a way to avoid a stall waiting for the render commands to flush when setting a skinned mesh? More generally, what is the recommended way to spawn and set up characters like this during a game? The characters we use are metahuman based, so they may have fairly complex skeletons and meshes, and can take a while to initialize.

Customer will have to validate, the fix was obvious, but repro is specific to their setup.