@Nullable
    default Long defaultConnectTimeoutMillis() {
        return null;
    }
Returns the default client-side timeout of a socket connection attempt in milliseconds.
Note that this flag has no effect if a user specified the value explicitly via
{@link ClientFactoryBuilder#channelOption(ChannelOption, Object)}.

<p>The default value of this flag is {@value DefaultFlagsProvider#DEFAULT_CONNECT_TIMEOUT_MILLIS}.
Specify the {@code -Dcom.linecorp.armeria.defaultConnectTimeoutMillis=<integer>} JVM option to override
the default value.
core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java