Adding CrimsonLog as an optional dependency

Step 1) Add CrimsonLog as a SOFT dependency. This ensures that Crimson will be loaded before your mod.

[BepInPlugin(MyPluginInfo.PLUGIN_GUID, MyPluginInfo.PLUGIN_NAME, MyPluginInfo.PLUGIN_VERSION)]
[BepInDependency("CrimsonLog", BepInDependency.DependencyFlags.SoftDependency)]
internal class Plugin : BasePlugin

Step 2) Create a way to check for CrimsonLog, this can be in your main plugin.cs or some other utility script.

public static bool LogLoaded = false;
public override void Load()
    {
        Instance = this;
        Settings = new Settings();
        _harmony = Harmony.CreateAndPatchAll(Assembly.GetExecutingAssembly());

        foreach (var plugin in IL2CPPChainLoader.Instance.Plugins)
	{
	        var metadata = plugin.Value.Metadata;
		if (metadata.GUID.Equals("CrimsonLog"))
		{
			// found it
			LogLoaded = true;
			break;
		}
	}

    }

Step 3)

Use Logger, as it's an optional dependency make sure your logs will go to bepinex if users don't use it.

public static class Logger
{
    public static void Log(string message, bool console = false)
    {
        if (Plugin.LogLoaded && CrimsonLog.Plugin.LogInstance != null && !console)
        {
            CrimsonLog.Systems.Logger.Record("ChatMonitor", "chat", message + "\n");
        }
        else
        {
            Plugin.LogInstance.LogInfo(message);
        }
    }
}