perf: decrease wantlist send debounce time (#224)

* perf: decrease wantlist send debounce time

We wait 200ms before sending wantlists to remote peers which is an
eternity. I'm not sure how this figure was arrived at but I've reduced
it to 10ms which has increased the js->js transfer times in the interop
tests to:

| Data    | 200ms    | 10ms    | Speedup |
|---------|----------|---------|---------|
| 1.02 kB | 486ms    | 142ms   | 342%    |
| 63.5 kB | 449ms    | 119ms   | 377%    |
| 65.5 kB | 436ms    | 105ms   | 415%    |
| 524 kB  | 1287ms   | 210ms   | 613%    |
| 786 kB  | 1676ms   | 282ms   | 594%    |
| 1.05 MB | 2066ms   | 326ms   | 634%    |
| 1.05 MB | 2123ms   | 330ms   | 643%    |
| 4.19 MB | 7091ms   | 1045ms  | 679%    |
| 8.39 MB | 13711ms  | 1927ms  | 712%    |
| 67.1 MB | 107704ms | 13462ms | 800%    |
| 134 MB  | 214988ms | 26038ms | 826%    |

* chore: PR comments

* chore: decrease debounce to 1ms

Author: achingbrain

src/constants.js

@@ -8,5 +8,6 @@ module.exports = {
   hasBlockTimeout: 15 * SECOND,
   provideTimeout: 15 * SECOND,
   kMaxPriority: Math.pow(2, 31) - 1,
-  maxListeners: 1000
+  maxListeners: 1000,
+  wantlistSendDebounceMs: 1
 }

src/want-manager/msg-queue.js

@@ -4,6 +4,7 @@ const debounce = require('just-debounce-it')
 
 const Message = require('../types/message')
 const logger = require('../utils').logger
+const { wantlistSendDebounceMs } = require('../constants')
 
 module.exports = class MsgQueue {
   constructor (selfPeerId, otherPeerId, network) {
@@ -13,7 +14,7 @@ module.exports = class MsgQueue {
 
     this._entries = []
     this._log = logger(selfPeerId, 'msgqueue', otherPeerId.toB58String().slice(0, 8))
-    this.sendEntries = debounce(this._sendEntries.bind(this), 200)
+    this.sendEntries = debounce(this._sendEntries.bind(this), wantlistSendDebounceMs)
   }
 
   addMessage (msg) {