========================================================================
Namespace declaration
========================================================================
namespace Microsoft.Sales;
------------------------------------------------------------------------

(source_file
  (namespace_declaration
    (namespace_keyword)
    name: (namespace_name
      (identifier)
      (identifier))))

========================================================================
Using statement
========================================================================
using Microsoft.Foundation.Period;
------------------------------------------------------------------------

(source_file
  (using_statement
    (using_keyword)
    namespace: (namespace_name
      (identifier)
      (identifier)
      (identifier))))

========================================================================
Namespace with using
========================================================================
namespace MyApp.Core;

using Microsoft.Sales;
using System.IO;
------------------------------------------------------------------------

(source_file
  (namespace_declaration
    (namespace_keyword)
    name: (namespace_name
      (identifier)
      (identifier)))
  (using_statement
    (using_keyword)
    namespace: (namespace_name
      (identifier)
      (identifier)))
  (using_statement
    (using_keyword)
    namespace: (namespace_name
      (identifier)
      (identifier))))

========================================================================
Simple namespace (single segment)
========================================================================
namespace MyApp;
------------------------------------------------------------------------

(source_file
  (namespace_declaration
    (namespace_keyword)
    name: (namespace_name
      (identifier))))
