Parse retry-after header

[tellet-q]

Add support for following responses from Qdrant:

Rate limiter hit for gRPC: qdrant/qdrant#6072

• Introduce QdrantError::ResourceExhaustedError for the client

Usage example for strict mode ("read_rate_limit": 60, "write_rate_limit": 60):

use qdrant_client::{Qdrant, QdrantError};
use qdrant_client::qdrant::QueryPointsBuilder;

#[tokio::main]
async fn main() {
    let collection_name = "benchmark";

    let client = Qdrant::from_url("http://localhost:6334").build();

    match client {
        Ok(client) => {
            match client.collection_exists(collection_name).await {
                Ok(exists) => {
                    if exists {
                        println!("Collection '{}' exists!", collection_name);
                    } else {
                        println!("Collection '{}' does not exist.", collection_name);
                    }
                }
                Err(err) => {
                    eprintln!("Error checking collection existence: {:?}", err);
                }
            }

            match client.health_check().await {
                Ok(response) => {
                    println!("Qdrant is healthy: {:?}", response);
                }
                Err(err) => {
                    eprintln!("Qdrant is not healthy: {:?}", err);
                }
            }

            println!("start hit_rate_limit");
            for _ in 0..100 {
                let result = client.query(
                    QueryPointsBuilder::new("benchmark")
                        .query(vec![0.2, 0.1, 0.9, 0.7])
                ).await;

                match result {
                    Ok(_) => {},
                    Err(err) => {
                        match err {
                            QdrantError::ResourceExhaustedError { status: _, retry_after_seconds } => {
                                println!("Limit hit! Retry after: {:?} seconds", retry_after_seconds);
                                break;
                            },
                            _ => {
                                println!("Error: {:?}", err);
                                break;
                            }
                        }
                    }
                }
            }
            println!("done hit_rate_limit");
        }
        Err(err) => {
            eprintln!("Failed to create Qdrant client: {:?}", err);
        }
    }
}

All Submissions:

• Contributions should target the dev branch. Did you create your branch from dev?
• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

New Feature Submissions:

1. Does your submission pass tests?
2. Have you formatted your code locally using cargo +nightly fmt --all command prior to submission?
3. Have you checked your code using cargo clippy --all --all-features command?

Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
• Have you successfully ran tests with your changes locally?

[Anush008]

LGTM 🙏