so we had just 128 bytes for path to generic loader utility. in most
cases this is plenty but if you have bizarre symlinks and long paths
we may run out of space, so move up to 4k buffers as this is
realistically the max path len anyway on a system.
@fix
to date if you use async preload we still load the header
synchronously and this can be horrible especially with generic
loaders. there is no way to farm this off to the preload thread. now
there is. youhave to set it as a skip head load option before doing a
file_set AND you need to issue a preload ... but now it's possible.
@feature