Method FileUploadHandler.serializeResponse() checks for existing Content-Type headers but then sets the lower-case content-type headers.
As a result the response contains three header fields:
content-type: application/json; charset=UTF-8
content-type: application/json; charset=UTF-8
content-type: text/plain; charset=UTF-8
Method
FileUploadHandler.serializeResponse()checks for existingContent-Typeheaders but then sets the lower-casecontent-typeheaders.As a result the response contains three header fields: