"static_listeners": [
    {
     "listener": {
      "@type": "type.googleapis.com/envoy.config.listener.v3.Listener",
      "address": {
       "socket_address": {
        "address": "0.0.0.0",
        "port_value": 15090
       }
      },
      "filter_chains": [
       {
        "filters": [
         {
          "name": "envoy.filters.network.http_connection_manager",
          "typed_config": {

hex_exponent      = ( "p" | "P" ) [ "+" | "-" ] decimal_digits .
</pre>

<pre>
0.
72.40
072.40       // == 72.40
2.71828
1.e+0
6.67428e-11
1E6
.25
.12345E+5
1_5.         // == 15.0
0.15e+0_2    // == 15.0

0x1p-2       // == 0.25
0x2.p10      // == 2048.0
0x1.Fp+0     // == 1.9375
0X.8p-0      // == 0.5
0X_1FFFP-16  // == 0.1249847412109375