If you want to think about what the future of the Internet of Things (IoT) will look like, walk along Boston’s 400-year-old streets. With its deep elite academic and tech connections, the city is a natural place to experiment and see how people react to–or fail to notice–the network of sensors that experts say will be a trillion-dollar business sector by the end of the decade. Walk down the Rose Kennedy Greenway, an arterial strip of park space that winds through downtown Boston, and soon you’ll come to a Soofa, a park bench that does a lot of work while people are sitting on it. Parked in the greens for the first time this month, the solar panels that cover the Soofa drink in energy from the sky and channel it into USB ports that charge your phone.