Allow MAX_ALLOWED_ATTRIBUTES to be configurable

[cdarrigo]

Messages may have more than 9 attributes, when using the attributes to pass context outside the message body (security, logging, additional context).

The max attribute count should be configurable, rather than a hardcoded constant.

[raol]

Hi @cdarrigo
I'm afraid the change you're proposing is not possible to implement. According to the sqs developer guide maximum number of attributes for an SQS message is 10. This package reserves 1 attribute as its own, to be able to pass S3 object handle in there. That leaves us with 9 allowed attributes max, as specified in the constants.