Gated

Attaches gates to a handler. The gates run before execute, and a gate refusing stops the handler with the reply or drop the gate threw. Multiple gates are ANDed, so each must pass. A gate that requires a context the handler does not provide (a button gate on a slash handler, an interaction gate on an event handler) is a compile error at this line, and the error names the gate and the handler kind. Place it above the route decorator.

Combine gates with and or or to build a single gate from multiple arms.