'Configure Edns.
@param edns: The EDNS level to use.  The default is -1, no Edns.
@type edns: int
@param ednsflags: The EDNS flags
@type ednsflags: int
@param payload: The EDNS payload size.  The default is 0.
@type payload: int'

def use_edns(self, edns, ednsflags, payload):

    if (edns is None):
        edns = (-1)
    self.edns = edns
    self.ednsflags = ednsflags
    self.payload = payload
