Set the user_agent property by appending the application details.
Set the user_agent property by appending the application details to the
default user agent. If no application name is given, the default user agent will be used and application_version is ignored.
If only the name is given, the default engine version is used with the given application name.
| this |
a Settings |
| application_name |
The application name used for the user agent or null to use the default user agent. |
| application_version |
The application version for the user agent or null to use the default version. |