Revert to previous Director() based proxy logic for all requests that are not 'Expect: 100-continue', and also use that logic when KeepAlive100Continue is enabled.
Differences between Director() and Rewrite() are very low level, and this mitigates against the risk of any untested behaviors causing breaking changes, while opting into closing connections on 100-continue based requests.
Backward Compatibility
Reverts the httputil.ReverseProxy behavior as closely as possible to how it was previously.
Summary
Revert to previous Director() based proxy logic for all requests that are not 'Expect: 100-continue', and also use that logic when KeepAlive100Continue is enabled.
Differences between Director() and Rewrite() are very low level, and this mitigates against the risk of any untested behaviors causing breaking changes, while opting into closing connections on 100-continue based requests.
Backward Compatibility
Reverts the httputil.ReverseProxy behavior as closely as possible to how it was previously.