Microsoft.CodeAnalysis.SolutionExplorer.AbstractSolutionExplorerSymbolTreeItemProvider<TCompilationUnitSyntax, TMemberDeclarationSyntax, TNamespaceDeclarationSyntax, TEnumDeclarationSyntax, TTypeDeclarationSyntax, TMemberStatement>.AddNamespace(Microsoft.CodeAnalysis.DocumentId, TNamespaceDeclarationSyntax, Microsoft.CodeAnalysis.PooledObjects.ArrayBuilder<Microsoft.CodeAnalysis.SolutionExplorer.SymbolTreeItemData>, System.Text.StringBuilder)