Description:
------------
using ftp_nb_fget() to download a file from ftp always gets only 2,920 bytes. 

Reproduce code:
---------------
$rStream = fopen('test.zip','x');
ftp_nb_fget($rFtp,$rStream,$fullPath(),FTP_BINARY);
sleep(58);

Expected result:
----------------
Download complete file.

Actual result:
--------------
Downloads only 2,920 bytes, the file size doesn't influence this result unless less than 2,920 in witch case the function works as expected. Also tried with FTP_ASCII same result.