How should bcf::Record::push_info_float work?

[xosxos]

In the documentation it says under bcf::record::Record::push_info_float

Add/replace a float-typed INFO entry.

However when trying to add an INFO field from another VCF file I get the following error:

 let af = record_1.info(b"my_tag")).float().unwrap().unwrap();
 let af: Vec<f32> = info.iter().copied().collect();            
 record_2.push_info_float(b"my_tag"), &af).unwrap();

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: BcfSetTag { tag: "my_tag" }'

I haven't followed the source code beyond the hts_sys bindings to C, however I was hoping there is some simple explanation to this specific error. Should the tag be defined in the Record header before trying to push? The same error applies to all push_info functions when adding fields. Replacing seems to work fine.

[ebioman]

Hi, any record you push has first to be defined in the header