RIO DE JANEIRO — When I visited China in June, my trip happened to coincide with the discovery that Edward Snowden was hiding out in Hong Kong. By then, Snowden’s revelations about the voracious data-collection operation by the National Security Agency was front-page news all over the world. Snowden hadn’t yet been charged for the leak of tens of thousands of pages of classified N.S.A. documents, but it was clear that it was coming. So it was only natural to ask — as many journalists did — would Hong Kong give Snowden asylum if he requested it?