Hi everyone, I've just come across this sentence "It has led to major websites and services – including Imgur, Medium and the Docker Registry Hub – falling offline, losing images, or left running like treacle." They mean the outage of Amazon S3, in case it's relevant. I understand what "treacle" generally means, but how is it used in this sentence? Is this some idiomatic expression (of which I cannot find any traces online) or just a metaphor? And if it is a metaphor, what would be the synonym? I'm asking because I'm not English, so I need help with understanding this phrase, but I kind of like it and would like to use it myself if it makes sense in a context other than that one Thanks a lot in advance!