
PASS underlying sink's write should not be called until start finishes 
PASS underlying sink's close should not be called until start finishes 
PASS underlying sink's write or close should not be called if start throws 
PASS underlying sink's write or close should not be invoked if the promise returned by start is rejected 
PASS returning a thenable from start() should work 
PASS controller.error() during start should cause writes to fail 
PASS controller.error() during async start should cause existing writes to fail 
PASS when start() rejects, writer promises should reject in standard order