Support the @ structure capturing operator

[darraghjones]

According to https://messagetemplates.org/

Prefixing a property name with the @ structure capturing operator is a hint that the the structure of the corresponding argument should be preserved, for example, by serialization

What do you think about adding support for this?

[mattwcole]

I don't think that sounds unreasonable, especially if it is something other providers support. I've not used Graylog for years so I don't know how it would handle this though. The examples in the GELF spec only show sending key value pairs.

[mattwcole]

Closing for now, let me know if you have some ideas on how this would work. Can re-open if there is still interest.