def apply(zocket)
      raise ArgumentError, "invalid zocket argument %p" % zocket unless zocket
      return ffi_delegate.apply(zocket) unless secret_key.nil?
      raise_zmq_err("secret key is undefined")
    end
def apply(zocket)
      raise ArgumentError, "invalid zocket argument %p" % zocket unless zocket
      return ffi_delegate.apply(zocket) unless secret_key.nil?
      raise_zmq_err("secret key is undefined")
    end
Applies this certificate on a {Socket} or {Actor}.
 @param zocket [Socket, Actor] path/filename to secret file
 @return [void]
 @raise [SystemCallError] if secret key is undefined