code: func (c *ClientContext) MakeSignature(msg []byte, qop, seqno uint32) ([]byte, error) {
  	return makeSignature(c.sctxt, msg, qop, seqno)
  }
docs: // MakeSignature uses the established client context to create a signature
  // for the given message using the provided quality of protection flags and
  // sequence number. It returns the signature token in addition to any error.