I have seen this pattern a few times. 아/어/해 + ㅆ + 듯이 I know 듯이 means meaning but is this a grammatical form to learn? At the start of this podcast they use 예고했듯이 as well

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I have seen this pattern a few times.

아/어/해 + ㅆ + 듯이

I know 듯이 means meaning but is this a grammatical form to learn?
At the start of this podcast they use 예고했듯이 as well