public override object VisitField(IFieldSymbol fieldSymbol)
 {
     WriteType(SymbolKeyType.Field);
     FieldSymbolKey.Create(fieldSymbol, this);
     return(null);
 }
 public override void VisitField(IFieldSymbol fieldSymbol)
 {
     WriteType(SymbolKeyType.Field);
     FieldSymbolKey.Create(fieldSymbol, this);
 }