My chest-high fishing waders and rubber boots clashed sharply with the smartly dressed people on the elegant streets of Treviso, Italy. I felt like a character from “A River Runs Through It” dropped onto the set of “La Dolce Vita.” I swung a leg over the stone parapet and wrought iron railing of Ponte Sant’Agata and, clasping my fly rod, gently lowered myself to the cutwater at the base of a bridge pier.