@Deprecated
    public static boolean useEpoll() {
        return USE_EPOLL;
    }
Returns whether the JNI-based {@code /dev/epoll} socket I/O is enabled. When enabled on Linux, Armeria
uses {@code /dev/epoll} directly for socket I/O. When disabled, {@code java.nio} socket API is used
instead.

<p>This flag is enabled by default for supported platforms. Specify the
{@code -Dcom.linecorp.armeria.useEpoll=false} JVM option to disable it.

@deprecated Use {@link #transportType()} and {@code -Dcom.linecorp.armeria.transportType=epoll}.
core/src/main/java/com/linecorp/armeria/common/Flags.java