`Variant$send_mail()` failing

[kmasiello]

Attempting to follow a two-step process of

1. render a variant
   Code below is successful

# get content item
content <- content_item(con, content_guid)

# select the default variant to re-render
content_variant <- get_variant_default(content)

# trigger new rendering of variant
new_render <- variant_render(content_variant)

2. send email of variant
   Code below fails

new_render$send_mail("me")

Error

List of 3 $ code   : int 12 $ error  : chr "A required parameter is missing." $ payload: NULL
Error in `self$raise_error()`:
! https://thankful-terrier.staging.eval.posit.co/pub/__api__/variants/3/sender request failed with Client error: (400) Bad Request
Show Traceback

The POST request appears to be malformed and the parameters email and rendering_id don't seem to be appended.