[ECS] : mTLS support for ECS Service Connect

### Community Note

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**Tell us about your request**
Traffic encryption with mTLS support for services running with ECS Service Connect .

**Which service(s) is this request for?**
ECS

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
What outcome are you trying to achieve, ultimately, and why is it hard/impossible to do right now? What is the impact of not having this problem solved? The more details you can provide, the better we'll be able to understand and solve the problem.

**Are you currently working around this issue?**
Researching

**Additional context**
Anything else we should know?

**Attachments**
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