VRC0021: Unable to send network event to UdonBehaviour with SyncType 'None'

Property	Value
ID	VRC0021
Category	Unexpected
Severity	Warning
Runtime Version	3.1.0 ~ latest

Unable to send network event to UdonBehaviour '{0}' with SyncType 'None'

Example

Code with Diagnostic

using UdonSharp;

using VRC.Udon.Common.Interfaces;

class TestBehaviour1 : UdonSharpBehaviour
{
    private TestBehaviour2 _other;

    public void SomeMethod()
    {
        _other.SendCustomNetworkEvent(NetworkEventTarget.All, "SomeMethod");
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    }
}

[UdonBehaviourSyncMode(BehaviourSyncMode.None)]
class TestBehaviour2 : UdonSharpBehaviour
{
    public void SomeMethod() {}
}

Code with Fix

// NOT YET PROVIDED