feat: improve performance by introducing support for UDS

[dyxushuai]

Unix Domain Socket (Only work in UNIX environment)

For local communication, UDS provides ~18-20% lower latency compared to TCP:

{
  "grpc": {
    "transport": "uds",
    "uds": {
      "socket_path": "/tmp/yellowstone-grpc.sock",
      "remove_on_startup": true
    }
  }
}

Client connection via UDS:

// Rust client
let client = GeyserGrpcClient::build_from_static("unix:///tmp/yellowstone-grpc.sock")?
    .connect()
    .await?;

Benchmark Results (TCP vs UDS)

Metric	TCP	UDS	Improvement
Ping Latency	37.3 µs	30.6 µs	18% faster
Throughput	27.0 K/s	32.4 K/s	20% higher

[Copilot]

Pull request overview

This PR adds Unix Domain Socket (UDS) transport support to the gRPC server, providing an ~18-20% performance improvement for local communication compared to TCP. The implementation maintains backward compatibility with existing TCP-based configurations.

Key changes:

• Adds a configurable transport layer with support for both TCP (default) and UDS
• Implements socket file management including cleanup and directory creation
• Includes comprehensive benchmarks demonstrating the performance improvements

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
yellowstone-grpc-geyser/src/config.rs	Adds TransportType enum and ConfigUds struct for transport configuration; makes address optional while maintaining backward compatibility
yellowstone-grpc-geyser/src/grpc.rs	Implements UDS server binding logic with socket file handling; refactors server spawning into a macro to support both transport types
yellowstone-grpc-geyser/config.json	Updates example config to show TCP transport configuration explicitly
yellowstone-grpc-geyser/config-uds.json	Adds new example configuration for UDS transport
benches/transport.rs	Adds performance benchmarks comparing TCP and UDS latency and throughput
benches/Cargo.toml	Adds benchmark package with required dependencies
README.md	Documents the new transport options with examples and benchmark results; fixes spacing in documentation
Cargo.toml	Adds benchmark package to workspace and includes new dependencies
Cargo.lock	Updates lock file with new dependencies for benchmarking

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[leafaar]

Thank you very much for the contribution! I am taking a read.

[leafaar]

I want to thank you for the PR again @dyxushuai. I will close this PR because we end up implementing ourselves, it was easier to iterate.

Here's the PR: #671

I know it's already merged but if you have any comments please let us know!