Description:
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It looks like this was an issue in the past that was resolved [1], but it looks like this is still a problem. If you run attached code on a mailbox of a few hundred messages, you can see the mem grow continuously. Using `imap_savebody()` also leaks.

[1] https://bugs.php.net/bug.php?id=47940

Test script:
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$imap = imap_open(IMAP_PATH, IMAP_USER, IMAP_PASS);
$uids = imap_sort($imap, SORTARRIVAL, 1, SE_UID | SE_NOPREFETCH);
$len = count($uids);

for ($i = 0; $i < $len; $i++)
  $raw = imap_fetchbody($imap, $uids[$i], "", FT_UID | FT_PEEK);