Recommended way to set the headers?

[grapho]

How can i set headers on the x-xhr-http-request component? I tried to pass headers with a (hash) helper.

Specifically, I passed in this:

{{x-xhr-http-request ... headers=(hash Accept="file/download; version=1.0.0") ...}}

but I got this error:

Uncaught InvalidStateError: Failed to execute 'setRequestHeader' on 'XMLHttpRequest': The object's state must be OPENED.

I debugged and breakpointed all the way to the fail point in XRequest

XRequest.prototype.setRequestHeader = function setRequestHeader(name, value) {
      return this.state.xhr.setRequestHeader(name, value);
    };

and confirmed that it was receiving the name "Accept" and the value "file/download; version=1.0.0"

https://github.com/cowboyd/x-request.js/blob/master/src/x-request.js#L55-L57

The error originated from XRequest, so I posted the issue there, just not sure where to go from here?