@Nullable
    default Boolean useDefaultSocketOptions() {
        return null;
    }
Returns whether default socket options defined by Armeria are enabled.
If enabled, the following socket options are set automatically when
{@code /dev/epoll} or {@code io_uring} is in use:
<ul>
  <li>TCP_USER_TIMEOUT</li>
  <li>TCP_KEEPIDLE</li>
  <li>TCP_KEEPINTVL</li>
</ul>

<p>This flag is enabled by default.
Specify the {@code -Dcom.linecorp.armeria.useDefaultSocketOptions=false}
JVM option to disable it.</p>
core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java