[BUG] request_signer inconsistent body serialization

[szechyjs]

What is the bug?

The body that is being used by the request signer is not the same as the one being sent on the wire. This results in a invalid signature 403 error.

How can one reproduce the bug?

Use the latest beta versions of the gems.

What is the expected behavior?

The body used in the signature generation should be the same as the one actually sent to server.

Do you have any additional context?

This was originally fixed in opensearch-project/opensearch-ruby-aws-sigv4#24 However, the new rewrite of this functionality has caused a regression. The request_signer is calling body.to_json on the body, however the transports are using __convert_to_json(body).

Original issue #141

[Earlopain]

Sorry for the late reply @szechyjs. I don't use the signer personally so I am not very familiar with it. Could you provide me some steps to reproduce the issue?

cc @nhtruong since you fixed the original issue