Signing issue with apigatewaymanagementapi

[chirag729]

I've just upgraded from using the old individual aws packages you published to this single aws_client package. Most things work but I'm having trouble with apigatewaymanagementapi.

I get the following error when trying to post a websocket message from my backend to my app.

1728730575106,"403 InvalidSignatureException: The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. Consult the service documentation for details.
1728730575106,"The Canonical String for this request should have been
1728730575106,"'POST
1728730575106,"/%2540connections/fiJTcdBJIAMCEVw%253D
1728730575106,"accept:application/json
1728730575106,"host:wsapi-staging.omnichess.club
1728730575106,"x-amz-content-sha256:7be239a78828305db57e414ac165d5c13b22786c25c8270b4806b186c2aea2c8
1728730575106,"x-amz-date:20241012T105615Z
1728730575106,"accept;host;x-amz-content-sha256;x-amz-date;x-amz-security-token
1728730575106,"7be239a78828305db57e414ac165d5c13b22786c25c8270b4806b186c2aea2c8'
1728730575106,"The String-to-Sign should have been
1728730575106,"'AWS4-HMAC-SHA256
1728730575106,"20241012T105615Z
1728730575106,"20241012/us-east-1/execute-api/aws4_request
1728730575106,"398ee4fbb2e5052b1b8fa49d5c4f55757aafa1acc9b9c297a0452fc8ae424827'
1728730575106,"#0      throwException (package:aws_client/src/shared/src/protocol/shared.dart:324)

If i switch back to using the old aws_apigatewaymanagementapi_api package, everything works as expected.

Complete logs:
log-events-viewer-result.csv