code: func (h *encHandshake) staticSharedSecret(prv *ecdsa.PrivateKey) ([]byte, error) {
  	return ecies.ImportECDSA(prv).GenerateShared(h.remote, sskLen, sskLen)
  }
docs: // staticSharedSecret returns the static shared secret, the result
  // of key agreement between the local and remote static node key.