Describe the bug
We use some custom parameters via axios configuration. They are used in the response interceptor. Sometimes there may be a lot of information there, so the option to pass it through the headers or params is not suitable for us because of the length limit

To Reproduce

• Open: https://jsfiddle.net/w2rmhy4c/1/
• Attach axios 0.18 (uncomment line with [email protected])
• Run fiddle (console show true)
• Attach axios 0.19 (uncomment line with [email protected])
• Run fiddle (console show undefined)

Expected behavior
Custom config parameter passed. Or the ability to use another config option to pass custom data.

Environment:

• Axios Version 0.18/0.19

Additional context/Screenshots
First messages with axios 0.18, second with 0.19