JBPayHookSpecification
A pay hook specification sent from the ruleset's data hook back to the terminal. This specification is fulfilled by the terminal.
Notes:
- 
member: hook The pay hook to use when fulfilling this specification.
 - 
member: amount The amount to send to the hook.
 - 
member: metadata Metadata to pass the hook.
 
struct JBPayHookSpecification {
    IJBPayHook hook;
    uint256 amount;
    bytes metadata;
}