# Functions
NewRegistry creates and initializes a new Registry.
# Variables
ErrTypeAlreadyDefined is returned when an already defined message type is redefined.
ErrUnknownType is returned when a definition for an unknown message type is requested.
# Structs
Definition describes a message's ID, its max byte length and whether its size can be variable.
Registry holds message definitions.
# Type aliases
Type denotes the byte ID of a given message type.