NotSupportedException: IL2CPP does not support marshaling delegates that point to instance methods to native code. The method we’re attempting to marshal is: Steamworks.Callback

NotSupportedException: IL2CPP does not support marshaling delegates that point to instance methods to native code. The method we're attempting to marshal is: Steamworks.Callback`1[[Steamworks.MicroTxnAuthorizationResponse_t, Assembly-CSharp-firstpass, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null]]::OnRunCallResult

Unity2019.4.16 HDRP steamworks.net 14.0.0 DRM有効、IL2cpp

DRM有効にしてsteamworksに登録し、steamClientから実行したら発生しました。正直これ以外にもエラーが噴出して死にます。

Unity 2018.1 and IL2CPP · Issue #227 · rlabrecque/Steamworks.NET

API doesnot work with Unity 2018.1 and IL2CPP enabled. NotSupportedException: To marshal a managed method, please add an attribute named 'MonoPInvokeCallback' t...

github.com

どうも古くからある問題だったようです。つらいです。

対処法

GitHub - rlabrecque/Steamworks.NET: Steamworks wrapper for Unity / C#

Steamworks wrapper for Unity / C#. Contribute to rlabrecque/Steamworks.NET development by creating an account on GitHub.

github.com

releaseではなくてmaster branchから落としたバージョンなら直ってます。もうしばらくすればReleaseに移るのではないかと思います。