Returns the HAR Transferred Size


*Example:*
| New HAR                | myHARFile                |
| Navigate To            |                          |
| Get HAR                |                          |
| Save HAR               |                          |
| ${harTransferredSize}= | Get HAR Transferred Size |

For integrated HAR support, the following properties should be enabled/defined
*jspringbot.properties*
selenium.browser.mob.proxy.enabled=true
selenium.browser.mob.proxy.har.save.dir=/Users/shielabuitizon/workspace/jspringbot-selenium/target/robotframework-reports/har

!!! Note:
* Should not be used with "Proxy Properties" and "Saucelabs Properties" since HAR support is already using Selenium Proxy

