Despite shutdowns that spread across the world last year and caused the performing arts industry to grind to a halt, finding a musician with idle hands remained as difficult a task as ever. “Some of my colleagues said, ‘Oh, I can finally play “Hammerklavier,”’ or, ‘In lockdown, I learned book one or two of “The Well-Tempered Clavier” by Bach,’” said celebrated pianist Janara Khassenova with a laugh. Pianists with schedules packed full of travel, concerts, and teaching appointments suddenly found that they had time for the special projects they’d put off for years, like learning a cycle of works by a favorite composer or some classics that never made it to program. “We can’t slow down just because of a lockdown.” Musicians like Khassenova are artists by nature, and the creative impulse doesn’t wait. When musicians saw their old livelihoods go up in smoke as every event was canceled worldwide, …