AWS X-Ray SDK Express Middleware

The `aws-xray-sdk-express` package provides middleware functions for Express.js applications to integrate with AWS X-Ray, enabling distributed tracing for incoming requests and outgoing responses. As part of the broader `aws-xray-sdk-node` monorepo, its current stable version is 3.12.0, with regular updates following the main SDK. It supports both automatic and manual tracing modes. The automatic mode, which is the default, utilizes the `cls-hooked` package for automatic context propagation across asynchronous operations, simplifying segment and subsegment management. Key differentiators include its official AWS support, seamless integration with Express.js routing, and the flexibility to choose between automatic and manual tracing paradigms to suit different application complexities and debugging needs. It requires Express 4.14.0 or greater and `aws-xray-sdk-core` as a peer dependency.