$handle = null
Set the resource handle to retrieve the data for the download.
The resource handle supplied will be closed after sending the download.
Set $handle to null if you want to unset.
Note: This cannot be used with resources of databases that populate their BLOBs as resource handles like PostgreSQL. A possible solution would be to write a stream wrapper.
Returns a PEAR_Error if $handle is no valid resource or not null.
mixed $handle = null - (int) resource handle or null
Returns TRUE on success, PEAR_Error on failure.
This function can not be called statically.