Update firehose client to accept start param and remove keep-alive

[Harsh24893]

💸 TL;DR

• Adding start option to the client. Start can take in a timestamp or id of the last event received. If it is empty, it ll start streaming from the current timestamp
• Removed keep alive as it is available by default

🧪 Testing Steps / Validation

Tested by npm start and fetching in a token id and subscription id

[adamthesax]

A few changes. Also can you verify we still need this:

// keeps node process alive to restart the stream	// keeps node process alive to restart the stream
setInterval(() => {}, 1 << 30);	setInterval(() => {}, 1 << 30);

Not entirely sure if it's needed

[adamthesax]

suggestion: Let's lean into command line arguments and away form environment variables

It makes it easier to understand what the program needs (--help) versus reading docs/docs

[adamthesax]

issue: This will always reconnect to whatever start value is passed in leading to duplicate messages. What we want to do is keep start up-to-date with the last Id seen.

Something like:

let start = program.opts.start

async function listen() {
  const stream = await initStream();
  stream
    .on('data', (chunk) => {
        const data = JSON.parse(chunk.toString());
        start = data.id
        })
 }

async function initStream() {
...blahblahblah...
   params: { start }
}[

[adamthesax]

One other thought is we should move away from assuming a chunk is a message and use a line reader for this. See readline

It's more accurate/robust and better represents our protocol.