text: #include <iostream>
  #include <string>
  #include <gtl/phmap.hpp>
  
  using gtl::flat_hash_map;
   
  int main()
  {
      // Create an unordered_map of three strings (that map to strings)
      flat_hash_map<std::string, std::string> email = 
      {
          { "tom",  "tom@gmail.com"},
          { "jeff", "jk@gmail.com"},
          { "jim",  "jimg@microsoft.com"}
      };
   
      // Iterate and print keys and values 
      for (const auto& n : email) 
          std::cout << n.first << "'s email is: " << n.second << "\n";
   
      // Add a new entry
      email["bill"] = "bg@whatever.com";
   
      // and print it
      std::cout << "bill's email is: " << email["bill"] << "\n";
   
      return 0;
  }
  