Trait for deterministically serializing an object to a com.google.protobuf.ByteString.

A class should extend this trait to indicate that the serialize method yields the same ByteString if invoked several times. Typical use cases of this behavior include:

• Classes that represent a leaf of a Merkle tree.
• Classes that represent content that is signed e.g. Hash or SignedProtocolMessageContent.
• Classes that are mere wrappers of ByteString (for convenience of the caller) e.g. AuthenticationToken.

If a class merely represents content that is transmitted over a network, the class does not need to extend this trait.

It is strongly recommended to extend this trait by mixing in ProtocolVersionedMemoizedEvidence or MemoizedEvidenceWithFailure, instead of directly extending this trait.

Classes C implementing HasCryptographicEvidence must define a fromByteString: ByteString => C method in their companion object that converts a serialization back into an equal object. In particular, c.fromByteString(byteString).toByteString must equal byteString.