'Based on the burst\'s size, return a ready-to-send padding blurb.'

def getPadding(self, sendCrypter, sendHMAC, dataLen):

    padLen = self.calcPadding(dataLen)
    assert (const.HDR_LENGTH <= padLen < (const.MTU + const.HDR_LENGTH)), ('Invalid    padding    length    %d.' % padLen)
    if (padLen > const.MTU):
        padMsgs = [message.new('', paddingLen=(700 - const.HDR_LENGTH)), message.new('', paddingLen=((padLen - 700) - const.HDR_LENGTH))]
    else:
        padMsgs = [message.new('', paddingLen=(padLen - const.HDR_LENGTH))]
    blurbs = [msg.encryptAndHMAC(sendCrypter, sendHMAC) for msg in padMsgs]
    return ''.join(blurbs)
