Represent the object that nodes gossip around the network.

### builder(): [MessageBuilder](#messagebuilder)

Creates a new `MessageBuilder` to construct an instance of a `Message`.

### networkId(): long

Returns the network id of a `Message`.

### id(): [MessageId](#messageid)

Computes the identifier of the message.

### nonce(): long

Returns the nonce of a `Message`.

### parents(): [MessageId[]](#messageid)

Returns the parents of a `Message`.

### payload(): Optional<[MessagePayload](#messagepayload)>

Returns the optional payload of a `Message`.