Issue of HttpApplication.GetVaryByCustomString

[Clounea]

Summary

In SharePoint Online repo, we override the HttpApplication.GetVaryByCustomString. But adapter does not support it. I'm not expert here so I would like to know where the method is used in .NetFramework and if it is needed in ASP.Net Core Application.

Motivation and goals

HttpApplication.GetVaryByCustomString is not supported in the adapter. I'm not expert here so I would like to know what the method is and if it is needed in ASP.Net Core Application.

Examples

In SharePoint, we override the function like

public override sealed string GetVaryByCustomString(HttpContext context, string custom)
{
            StringBuilder sb = new StringBuilder();
            try
            {
                foreach( var delegatefunction in _delegatefunctions)
                {
                    sb.Append( delegatefunction (this, context, custom ) );
                }
            }
            return sb.ToString();
}

[twsouthwick]

I'm adding this into #314

EDIT: Holding off on including it for now as we should understand how it could be surfaced in ASP.NET core in a way that makes sense before enabling the API for the API sake.