Function gen

packages/effect/src/Micro.ts:1222–1230

(
  ...args:
    | [self: Self, body: (this: Self) => Generator<Eff, AEff, never>]
    | [body: () => Generator<Eff, AEff, never>]
)

 * @category constructors
 */
export const gen = <Self, Eff extends YieldWrap<Micro<any, any, any>>, AEff>(
  ...args:
    | [self: Self, body: (this: Self) => Generator<Eff, AEff, never>]
    | [body: () => Generator<Eff, AEff, never>]
): Micro<
  AEff,
  [Eff] extends [never] ? never : [Eff] extends [YieldWrap<Micro<infer _A, infer E, infer _R>>] ? E : never,
  [Eff] extends [never] ? never : [Eff] extends [YieldWrap<Micro<infer _A, infer _E, infer R>>] ? R : never
> => suspend(() => fromIterator(args.length === 1 ? args[0]() : args[1].call(args[0]) as any))

const fromIterator: (
  iterator: Iterator<any, YieldWrap<Micro<any, any, any>>>