private static boolean canAddChannelOption(@Nullable ChannelOption<?> channelOption,
                                               Map<ChannelOption<?>, Object> channelOptions) {
        return channelOption != null && !channelOptions.containsKey(channelOption);
    }
Finds the {@link SSLSession} of the current TLS connection.

@return the {@link SSLSession} if found, or {@code null} if not found or {@link Channel} is {@code null}.
core/src/main/java/com/linecorp/armeria/internal/common/util/ChannelUtil.java