Amazon has spent years honing the business of packing, shipping and delivering millions of products to doorsteps around the world. Now it has a captive audience. With much of the globe in various stages of a lockdown because of the coronavirus pandemic, the world’s largest online retailer has become a lifeline to many shoppers. But it is also grappling with delivery delays and mounting complaints from workers who worry about contagion while on the job. Online research company Comscore reports that Amazon’s website hit 2.54 billion visitors for the entire month of March. That marks a 65% jump from the same period last year.