example: # matching `app.y.z`
  # optional, defaults to http
  scheme: http
  # required, proxy target
  host: 10.0.0.1
  # optional, defaults to 80 for http, 443 for https
  port: "80"
  # optional, defaults to empty
  path:
  # optional (scheme=https only)
  # no_tls_verify: false
  # optional headers to set / override (http(s) only)
  set_headers:
    HEADER_A:
      - VALUE_1
      - VALUE_2
    HEADER_B: [VALUE_3]
  # optional headers to hide (http(s) only)
  hide_headers:
    - HEADER_C
    - HEADER_D
app1: # matching `app1.y.z` -> http://some_host
  host: some_host
app2:
  scheme: tcp
  host: 10.0.0.2
  port: 20000:tcp