Say in the options table that a proven link resets the backoff

maxDelay bounds the wait and sets the bar a link must clear, and only the
first was documented, so tuning it up quietly lengthened every recovery.

The unreadable PDU the tests write is one named constant now.

README.md

@@ -104,7 +104,7 @@ Every one is optional.
 | `shutdownTimeout` | `5000` | How long `close()` and `unbind()` wait for the requests this end already sent; `0` waits forever. |
 | `maxOutstanding` | `10` | Requests allowed on the wire at once; further sends queue. |
 | `smsIdFormat` | — | The notation the SMSC writes message ids in, per place it writes them: `{ receipt: 'decimal', submitResp: 'hex' }`. Only needed where the two disagree. |
-| `reconnect` | on | Re-binds after a drop, an idle timeout, or a stream the library cannot read, backing off from `minDelay` 1 s to `maxDelay` 30 s. `{ minDelay, maxDelay }` retunes it; `false` turns it off, so a drop ends the session. |
+| `reconnect` | on | Re-binds after a drop, an idle timeout, or a stream the library cannot read, backing off from `minDelay` 1 s to `maxDelay` 30 s and starting over at `minDelay` once a link has lasted `maxDelay`. `{ minDelay, maxDelay }` retunes it; `false` turns it off, so a drop ends the session. |
 | `log` | silent | Any object with `debug`, `error`, `info`, `verbose` and `warn` methods — see [Logging](#logging). |
 | `signal` | — | An `AbortSignal` that cancels connecting and tears the session down. |
 

test/session-extras.test.ts

@@ -69,6 +69,9 @@ function delay(ms: number): Promise<void> {
 	return new Promise(resolve => { setTimeout(resolve, ms); });
 }
 
+/** A cmd_length below the 16-octet header: a stream no framing can recover from. */
+const unreadablePdu = Buffer.from([0, 0, 0, 4, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 1]);
+
 /** The server's side of the one connection under test. */
 function peerOf(smpp: SmppServer): Session {
 	const [peer] = smpp.sessions;
@@ -402,8 +405,7 @@ describe('reconnect', () => {
 
 		const reconnected = once<true>(resolve => { session.on('reconnected', () => { resolve(true); }); });
 
-		// A cmd_length below the 16-octet header is a stream no framing can recover from.
+		peerOf(smpp).sock.write(unreadablePdu);
-		peerOf(smpp).sock.write(Buffer.from([0, 0, 0, 4, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 1]));
 		await reconnected;
 
 		assert.deepEqual(events, ['sessionError']);
@@ -448,8 +450,7 @@ describe('reconnect', () => {
 
 		const closed = once<true>(resolve => { session.on('close', () => { resolve(true); }); });
 
-		// A cmd_length below the 16-octet header: unreadable, and nothing left to retry it.
+		peerOf(smpp).sock.write(unreadablePdu);
-		peerOf(smpp).sock.write(Buffer.from([0, 0, 0, 4, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 1]));
 		await closed;
 
 		assert.equal(disconnects, 0);

test/session.test.ts

@@ -1374,7 +1374,6 @@ describe('application hooks that throw or reject', () => {
 	});
 
 	test('keeps backing off when every link dies as soon as it comes up', async t => {
-		// A stream we cannot read is found after the bind, so a bind alone must not prove the link.
 		const clock = { now: 0 };
 		const delays: number[] = [];
 		const noop = (): void => undefined;