There's no one answer because there are two many variables. Where traffic permits, a medium sized pothole can be hopped over, or the quick swerve and recovery, where the bike goes around, and back under you before you fall, will work (takes a bit of bike handling skill).

Other obstacles need to be assessed (quickly) and a reflex like correction. Getting left crossed is fairly common where I do Sunday and evening rides, and I long ago decided to always move left and scrub off speed, and either pass behind the vehicle, or hit it. Three times now I've hit it broadside, once rolling over the hood, yet so far no injury, and lots for fear and apologies from drivers. One insisted on calling the police, and the officer asked both of us for our stories, which amazingly agreed, and promptly wrote the driver a ticket for unsafe left.

The biggest obstacle I ever encountered was 2 winters ago when riding home in the dark and rain and broadsided a slate gray van. At about 20 feet I suddenly realized that it wasn't a shadow (headlight glare on wet glasses) and not having time to avoid it turned parallel at the last moment and tried to body check it out of my way with my shoulder. Didn't work, but got off with no damage to bike and no injury, though I did dent the van. Driver was very good about it, taking some blame, and happy there wasn't injury. Rode home, and was fine except for waking up stiff on one side the next morning. Only lasting effect is that I no longer wear my glasses on rainy nights.