WP_Filesystem methods instead of direct PHP

When I run theme check it gives this warning.
How can I rewrite the call using WP system methods?

WARNING: file_get_contents was found in the file widget-my-info.php File operations should use the WP_Filesystem methods instead of direct PHP filesystem calls.

$requestpath = "http://url...."
$json_data = file_get_contents($requestpath);