Worked on the grafana/opentelemetry-rust repository to enhance the reliability of HTTP export functionality by addressing a critical bug in multi-header handling. Focused on improving the HttpExporterBuilder.with_headers method, the work ensured that multiple key-value header pairs are correctly processed and all configured headers are included in outgoing HTTP requests. This fix reduced export failures related to header transmission and improved interoperability with various HTTP backends. The engineering effort involved deep understanding of HTTP protocols, exporter configuration, and Rust programming, resulting in more robust OpenTelemetry integrations and smoother data export workflows for downstream systems. Markdown was used for documentation.