allow sending in multiple data points at once

[dougthor42]

It would be very nice if we could send in multiple data points at once.

With JSON, it's probably pretty easy. Structure could look like:

{
   "data":[
      {
         "metric": "foo.bar",
         "value": 15
      },
      {
         "metric": "foo.baz",
         "value": 9.16581
      },
      {
         "metric": "foo.foo",
         "value": -136.9981
      }
   ]
}

Obviously if the timestamp is not included then all values should have the same timestamp, as given by when the data was received.

With the plaintext protocol... it might be a little more difficult. Perhaps we separate things with a special character, set by the user in trendlines.cfg? Any whitespace after the character is ignored. In this example, I'm using semicolon ;:

echo "foo.bar 15; foo.baz 9.16581; foo.foo -136.9981" | nc $SERVER $PORT
echo "foo.bar 15 1550079504; foo.baz 9.16581 1550079504; foo.foo -136.9981 1550079504" | nc $SERVER $PORT