delegatee: The address in which the sender wishes to delegate their votes to.
nonce: The contract state required to match the signature. This can be retrieved from the contract’s public nonces mapping.
expiry: The time at which to expire the signature. A block timestamp as seconds since the unix epoch (uint).
v: The recovery byte of the signature.
r: Half of the ECDSA signature pair.
s: Half of the ECDSA signature pair.
RETURN: No return, reverts on error.