I am creating Message Object with raw(base64 encoded) & threadID field values. By using a valid threadId (of an existing email) , i was able to create a Threaded Message in users inbox.
After the 'Threading Changes' changed by google in April 2019, the messages are not threading. Instead they appear as individual messages, despite the ThreadID of both messages being same.
Google has recommended to add 'References' & 'In-Reply-To' header with value of 'Message-Id' from existing email. The Problem is, whenever we sent a new email using gmail api, we only receive message snipped back which only has ThreadID and Label values. To Retrieve 'Message-Id' of this sent email, another GET API call needs to be made. This is adding extra load to the system and un-necessarily making the system complex.
My Questions:
Is there any other way to Thread Messages using Gmail-APi?
Can we retrieve Message-ID without making another API Call?
Can we use any other headers /custom headers to establish a relationship between messages for them to thread.