Build a Simple HTTP Listener for Splunk HEC Events (Rust)

We need a small Rust service that listens for HTTP POST requests in the Splunk HEC format, parses the JSON payload, and prints each event to stdout.

Requirements:
• Listens on a configurable port
• Accepts HEC-style POST requests (JSON payloads)
• Parses and prints log events with metadata (timestamp, source, etc.)
• Handles errors gracefully
• Written in async Rust (tokio + hyper or axum)

Nice to have:
• Dockerfile
• Basic token-based auth
• Configurable input format (e.g., JSON array vs newline-delimited)

This is a standalone component for internal use—clean, idiomatic code and good structure matter.