Add Double Buffering for Live Metrics Document.

[rajkumar-rangaraj]

Added a double buffering system to enable writing to one buffer while simultaneously reading from another. Added the DocumentBuffer class for managing document ingress, along with the DoubleBuffer class to implement the double-buffering mechanism, allowing for concurrent writes to one buffer while the other is being read.

Usage

• To add documents: WriteDocument(DocumentIngress document)
• To flip buffers and process documents: FlipDocumentBuffers()

Impact

• Performance: Double buffering minimizes lock contention, leading to improved throughput and lower latency in high-concurrency environments.
• Reliability: Separates the concerns of writing and reading, reducing the complexity of synchronization.
• Maintainability: Encapsulates buffering logic within two clear methods, promoting cleaner code.

[TimothyMothra]

LGTM. Left one minor comment

[azure-sdk]

API change check

API changes are not detected in this pull request.