VRC0018: The method specified for SendCustomEvent is not declared in the behaviour

The method specified for SendCustomEvent is not declared in the behaviour

Example

Code with Diagnostic

using UdonSharp;

class TestBehaviour0 : UdonSharpBehaviour
{
    private TestBehaviour1 _behaviour;

    public void TestMethod()
    {
        _behaviour.SendCustomEvent("SomeMethod");
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    }
}

class TestBehaviour1 : UdonSharpBehaviour {}

Code with Fix

// NOT YET PROVIDED