code: @Override
      public ListRolesResult listRoles(ListRolesRequest request) {
          request = beforeClientExecution(request);
          return executeListRoles(request);
      }
docs: <p>
  Lists the IAM roles that have the specified path prefix. If there are none, the operation returns an empty list.
  For more information about roles, go to <a
  href="https://docs.aws.amazon.com/IAM/latest/UserGuide/WorkingWithRoles.html">Working with Roles</a>.
  </p>
  <p>
  You can paginate the results using the <code>MaxItems</code> and <code>Marker</code> parameters.
  </p>
  
  @param listRolesRequest
  @return Result of the ListRoles operation returned by the service.
  @throws ServiceFailureException
  The request processing has failed because of an unknown error, exception or failure.
  @sample AmazonIdentityManagement.ListRoles
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/iam-2010-05-08/ListRoles" target="_top">AWS API
  Documentation</a>