Usage of cachefs

Can someone show how to use cachefs storage type ?
According to documentation https://sdkdocs.roku.com/display/sdkdoc/File+System we can use cachefs for caching images. But  I can not simply create a task and save requested data in cachefs. For example like that.

function executeTask()    
    url = m.top.url
       
    request = CreateObject("roURLTransfer")
    request.SetCertificatesFile("common:/certs/ca-bundle.crt")
    request.AddHeader("X-Roku-Reserved-Dev-Id", "")
    request.AddHeader("Authorization","basic " + m.base64Vimeo)
    request.InitClientCertificates()
    request.SetURL(url)
    
    print("Setting Url in imagestore")
    print(url)
    
    m.top.response = request.getToFile("cachefs:/1.jpg")
    m.top.request = url
end function