Conflict:`middleware-conflict: key '${Key}' is already present on the upstream context`
Sentinel type used in a middleware's wrapper signature to surface a key
collision with the upstream context as a TypeScript error at the call site.
The literal string is part of the type so it appears in the error message
(TypeScript prints "Type '…' is not assignable to type 'middleware-conflict: …'").
Sentinel type used in a middleware's wrapper signature to surface a key collision with the upstream context as a TypeScript error at the call site.
The literal string is part of the type so it appears in the error message (TypeScript prints "Type '…' is not assignable to type 'middleware-conflict: …'").