"Message length exceeded maximum allowed length" error when saving large snapshot in Chrome and Edge

[dstillman]

https://forums.zotero.org/discussion/comment/437489/#Comment_437489

[JavaScript Error: "Error in invocation of runtime.sendMessage(optional string extensionId, any message, optional object options, optional function callback): Message length exceeded maximum allowed length.

If this is a recent lowering of some limit, we might need to send messages in multiple chunks?