HELOing with the JSON flag could be considered an API breaking change for a patch release

A recent change to gocbcore means that it now HELOs with the JSON flag. There's nothing inherently wrong with this, however, has caused some issues with 'cbbackupmgr' so thought it was worth bringing to attention. HELOing with the JSON flag means that clients which were originally restoring documents without the JSON bit set (i.e. informing the cluster the document is binary data) will no longer be processed by the cluster and marked as JSON if they are in fact valid JSON (i.e. the cluster now "trusts" us that it's a binary document and doesn't bother to check).

If this change will only affect users of unsupported operations such as SetWithMeta/DeleteWithMeta then I imagine it's fine, however, I do see that Set has a datatype field (I'm unaware of how that's handled by the SDK).

I'm also aware that the Agent configuration has an option to disable HELOing with the JSON flag, so there's obviously a workaround for user in the meantime but its not ideal if users are going to be unaware of the issue until they've already hit it.