Get the type of context after middleware

How can I get the type of the context of adminProcedure from export const adminProcedure = publicProcedure.use(isAdmin)? https://trpc.io/docs/server/middlewares
Middlewares | tRPC
You are able to add middleware(s) to a procedure with the t.procedure.use() method. The middleware(s) will wrap the invocation of the procedure and must pass through its return value.