All GREYMatchers, should assert immediatly, rather than wait.
There are side-effects of matchers that wait, because they can be chined with other methods.
For example, if you assert grey_nil() on a matcher that waits, the matcher will wait until a timeout (which are several seconds, or more), and then fail to match it. This will then succeed with grey_nil, but the delay is not optimal.
Comment 1 by liaoyuke@chromium.org
, Mar 10 2017