knplabs/Gaufrette — comment on commit 88622ed2b13357add386ccfb051ff49362a88d51
File: src/Gaufrette/FilesystemMap.php line 71
By stloyd:

AFAIK to not generate unnecessary overhead, you should not use calls for such simple internal operations (it's not big, but visible when you calls it many times), better would be to write exacly:
`if (false === isset($this->filesystems[$domain])) {`