Doing some rough and arbitrary testing I found that the workers have a request header limit of approximately 32kb.
I also found this:
Could someone confirm this and please add it to the FAQ? It’s rather useful.
Why? Uploading a file as the body, but you want to provide additional metadata. In your worker you will stream the file to storage, while entering the metadata in your DB.
Might be some general limit to make sure some system somewhere doesn’t get stuck going through cookies, but I can’t provide a definite answer.
What I can say for certain, though, is that this is common. See: Chen, Jianjun, et al. “Forwarding-Loop Attacks in Content Delivery Networks.” (2016), https://cybersecurity.uga.edu/publications/III.ndss2016.pdf,
Table 4, page 4