makeRecorderKit vs makeERecorderKit

[tgrecojs]

I've recently begun using recorder kits in an effort to achieve durable pub/sub operations. As the title suggests, I'm seeking clarity regarding the use of makeRecorderKit versus makeERecorderKit. Specifically, I'm wondering when the use of one is preferred over the other, and vice-versa.

I'm currently only using makeRecorderKit in my code which I'm obtaining via the prepareRecorderKitMakers function shown below.

agoric-sdk/packages/zoe/src/contractSupport/recorder.js

Lines 215 to 237 in 6f740a4

	export const prepareRecorderKitMakers = (baggage, marshaller) => {
	const makeDurablePublishKit = prepareDurablePublishKit(
	baggage,
	'Durable Publish Kit',
	);
	const makeRecorder = prepareRecorder(baggage, marshaller);
	const makeRecorderKit = defineRecorderKit({
	makeRecorder,
	makeDurablePublishKit,
	});
	const makeERecorderKit = defineERecorderKit({
	makeRecorder,
	makeDurablePublishKit,
	});
	return {
	makeDurablePublishKit,
	makeRecorder,
	makeRecorderKit,
	makeERecorderKit,
	};
	};

The reason for using prepareRecorderKitMakers stems from observing the approach taken in the inter-protocol code shown below. That said, I'm also curious as to how inter's codebase makes use of it (and the reasoning behind doing so).

agoric-sdk/packages/inter-protocol/src/vaultFactory/vaultFactory.js

Lines 90 to 93 in 6f740a4

	const { makeRecorderKit, makeERecorderKit } = prepareRecorderKitMakers(
	baggage,
	marshaller,
	);

Thanks! 🙂

[dckc]

@turadg do you have a handy answer for this one?

[turadg]

use makeRecorderKit unless you have a need specifically for an EventualRecorderKit.

agoric-sdk/packages/zoe/src/contractSupport/recorder.js

Lines 160 to 168 in fc69584

	/**
	* `makeERecorderKit` is for closures that must return a `subscriber` synchronously but can defer the `recorder`.
	*
	* @see {defineRecorderKit}
	*
	* @param {{makeRecorder: MakeRecorder, makeDurablePublishKit: ReturnType<typeof prepareDurablePublishKit>}} makers
	*/
	export const defineERecorderKit = ({ makeRecorder, makeDurablePublishKit }) => {
	/**

agoric-sdk/packages/zoe/src/contractSupport/recorder.js

Lines 29 to 38 in fc69584

	/**
	* @template T
	* @typedef {Pick<PublishKit<T>, 'subscriber'> & { recorder: Recorder<T> }} RecorderKit
	*/
	/**
	* @template T
	* @typedef {Pick<PublishKit<T>, 'subscriber'> & { recorderP: ERef<Recorder<T>> }} EventualRecorderKit
	*/