C# Core 3.5: Updated missing methods for error callback
C# Core 3.5: Updated missing methods for error callback

Identified during .net 3.5 compilation

marceloinacio/c-sharp,marceloinacio/c-sharp,grokify/c-sharp,grokify/c-sharp,grokify/c-sharp,marceloinacio/c-sharp,grokify/c-sharp,marceloinacio/c-sharp,marceloinacio/c-sharp,grokify/c-sharp