We do it this way (instead of set_site_transient) because of an issue where
sitewide transients are always autoloaded
https://core.trac.wordpress.org/ticket/22846
public set_transient ( string $transient, mixed $value, integer $expiration ) : boolean | ||
$transient | string | Transient name. Expected to not be SQL-escaped. Must be 45 characters or fewer in length. |
$value | mixed | Transient value. Must be serializable if non-scalar. Expected to not be SQL-escaped. |
$expiration | integer | Optional. Time until expiration in seconds. Default 0. |
리턴 | boolean | False if value was not set and true if value was set. |