/**
 * Resolves a function that accepts both the object argument fields of F1 and F2.
 * The function returns an intersection of what F1 and F2 return.
 *
 * @public
 */
export type MergeFunctions<F1, F2> = F1 extends (arg: infer A1) => infer R1 ? F2 extends (arg: infer A2) => infer R2 ? R1 extends Promise<unknown> ? (arg?: A1 & A2) => Promise<Awaited<R1> & Awaited<R2>> : (arg?: A1 & A2) => R1 & R2 : never : never;