Release 3.2.0

[3dgiordano]

This pull request introduces new features and documentation updates for the BlazeMeter HTTP plugin, focusing on improved control over timing and logging, along with dependency updates. The most significant changes are the addition of a new scheduler hold property for async controllers, expanded documentation on logging and debugging, and dependency upgrades for better stability and compatibility.

New features and configuration:

• Added support for a new property, blazemeter.http.schedulerHoldMillis, which controls how long the bzm - HTTP Async Controller will hold a thread at the end of a timed run to collect responses from in-flight requests, matching JMeter's graceful shutdown behavior. This is now documented and implemented in the code. [1] [2] [3] [4]

Documentation improvements:

• Expanded the README.md with a new section on Logging and low-level debugging, including detailed instructions on enabling internal plugin traces and controlling Jetty's logging verbosity. This helps users diagnose issues without overwhelming logs during load tests. [1] [2]
• Updated the Async Controller documentation to clarify timing behavior and new configuration options, including the new scheduler hold property and how timers/pre-post processors are included in parent sample timing. [1] [2]

Dependency and version updates:

• Upgraded the plugin version to 3.2.0 and updated the log4j dependency from 2.22.1 to 2.25.5 in pom.xml for improved security and compatibility. [1] [2]

Internal code enhancements:

• Refactored HTTP2Controller.java to support the new scheduler hold property, improved state tracking for parent transactions, and prepared for more granular control over sample timing and logging. [1] [2] [3] [4]

Connection Failure Tracking and Reporting

• Added the ConnectAttemptRecorder class to record all connection failures for each address attempted, and attach them as suppressed exceptions to the main failure, improving visibility into all failed connection attempts, not just the final one. (ConnectAttemptRecorder.java)
• Updated the HTTP/2 prior knowledge client transport instantiation to pass the ConnectAttemptRecorder, ensuring all connection attempts are captured. (HTTP2JettyClient.java)
• Replaced usages of HttpClientTransportDynamic with a new RecordingHttpClientTransportDynamic to support connection attempt recording across all protocol variants. (HTTP2JettyClient.java) [1] [2] [3] [4]

HTTP/2 Rejection Handling

• Implemented an onHttp2Rejected callback, which marks an origin as HTTP/1.1-only if it rejects the HTTP/2 preface, avoiding repeated failed attempts for future requests to that origin. (HTTP2JettyClient.java) [1] [2] [3]

Infrastructure and Constructor Updates

• Extended the HTTP2JettyClient constructor to accept a DnsResolver and initialize the ConnectAttemptRecorder and connector tracking, preparing the client for improved DNS and connection handling. (HTTP2JettyClient.java)

These changes together provide much richer error reporting and smarter protocol fallback behavior, improving both developer diagnostics and end-user experience.