# Functions
New creates a new handshake Service.
# Constants
MaxWelcomeMessageLength is maximum number of characters allowed in the welcome message.
ProtocolName is the text of the name of the handshake protocol.
ProtocolVersion is the current handshake protocol version.
StreamName is the name of the stream used for handshake purposes.
# Variables
ErrInvalidAck is returned if data in received in ack is not valid (invalid signature for example).
ErrInvalidSyn is returned if observable address in ack is not a valid..
ErrNetworkIDIncompatible is returned if response from the other peer does not have valid networkID.
ErrPicker is returned if the picker (kademlia) rejects the peer.
ErrWelcomeMessageLength is returned if the welcome message is longer than the maximum length.
# Interfaces
AdvertisableAddressResolver can Resolve a Multiaddress.