Proxy Headers get lost here.

[mlattanzio]

node-tunnel/lib/tunnel.js

Line 108 in 5fb2fb4

var connectOptions = mergeOptions({}, self.proxyOptions, {

mergeOptions leaves the proxyOptions.headers behind and they don't get send to the proxy server.

An ugly example fix would be
Object.assign(connectOptions.headers, self.proxyOptions.headers)
on the following line