FYI - I’ve tracked much of the delay to loading graphics as Asset(). The Asset() method of loading a graphic seems to work well locally and on a site that does NOT have an ssl-cert. Simply replacing the reference to the asset with a NetworkImage() method, and furnishing the full path (https://mysite.com/pathtoasset/assetname.ext) seems MUCH faster.
I created a simple test where I loaded an Asset() and a NetworkImage() to screen. The NetworkImage() loaded instantly, but the Asset() had a large time lag.
If this can be verified by the Flutter team, it may be a simple fix. This same type of problem may exist for fonts loaded as assets.
NOTE: This is only evident on a site that has an ssl-cert installed. I am testing with a GoDaddy hosted site, using a cert furnished and installed by GoDaddy.