module Flags:sig..end
type t 
Epoll.Flags.t is an immutable set of flags for which one can register
        interest for a file descriptor.  It is implemented as a bitmask, and so all
        operations (+, -, etc.) are constant time with no allocation.
        sexp_of_t produces a human-readable list of bits, e.g. "(in out)".
include Flags.S
val none : tval in_ : tval out : tval pri : tval err : tval hup : tval et : tval oneshot : tval sexp_of_t : t -> Sexplib.Sexp.t