private boolean tryComplete() {
            if (selected != null || isDone()) {
                return true;
            }

            try {
                final T selected = selectNow(ctx);
                if (selected == null) {
                    return false;
                }

                cleanup(false);
                // Complete with the selected endpoint.
                this.selected = selected;
                executor.execute(() -> super.complete(selected));
                return true;
            } catch (Throwable t) {
                cleanup(false);
                super.completeExceptionally(t);
                return true;
            }
        }
Triggers pending futures to try and select a value by calling {@link #selectNow(ClientRequestContext)}.
core/src/main/java/com/linecorp/armeria/internal/client/AbstractAsyncSelector.java