[Bug] SDK emit content_length in http response with string type instead of number.

[JohnWu20]

Xray SDK should send content_length with number type in the json segment for the http request data.

But I get this data when I use the latest node.js sdk version: data.txt

This is a bug and when our customers try to use OT collector to take place of Xray-daemon, they can't get the data they want.

[awssandra]

This looks correct, as per https://docs.aws.amazon.com/xray/latest/devguide/xray-api-segmentdocuments.html content-length should be recorded as a number.

We'll need to correct this in a few places:
https://github.com/aws/aws-xray-sdk-node/search?q=content_length