fuse_chan_find
struct fuse_chan* fuse_chan_find(bool (*pred)(struct fuse_chan* chan, void* priv),
chan = fuse_chan_find(is_same_mountpoint, &idx, __UNCONST(mountpoint));
chan = fuse_chan_find(is_same_fuse, NULL, fuse);
if (fuse_chan_find(is_same_channel, &idx, ch) == NULL)