NilRecipientsError thrown incorrectly for SendGrid emails

[emadalam]

As per the SendGrid usage, the send api allows us to skip the to, cc, bcc at the root level as long as the personalizations key with valid fields are provided. However the Mailer seem to be validating this at root level regardless of the adapter in use, and throws a NilRecipientsError.

Is there any workaround or quick fix for this? How can we send an email (common from, template_id etc) to multiple recipients via personalizations key, without setting the root level to, cc or bcc? The current personalizations implementation doesn't seem to fulfil the use case. Am I missing something?