chore: callbacks -> async / await

BREAKING CHANGE: All places in the API that used callbacks are now replaced with async/await

src/socket.js

@@ -0,0 +1,65 @@
+'use strict'
+
+const debug = require('debug')
+const log = debug('libp2p:tcp:socket')
+
+const c = require('./constants')
+
+class Libp2pSocket {
+  constructor (rawSocket, ma, opts) {
+    this._rawSocket = rawSocket
+    this._ma = ma
+
+    this.sink = this._sink(opts)
+    this.source = rawSocket
+  }
+
+  _sink (opts = {}) {
+    // By default, close when the source is exhausted
+    const closeOnEnd = opts.closeOnEnd !== false
+    return (source) => this._write(source, closeOnEnd)
+  }
+
+  async _write (source, closeOnEnd) {
+    for await (const data of source) {
+      const flushed = this._rawSocket.write(data)
+      if (!flushed) {
+        await new Promise((resolve) => this._rawSocket.once('drain', resolve))
+      }
+    }
+
+    if (closeOnEnd) {
+      await this.close()
+    }
+  }
+
+  close (opts = {}) {
+    if (this._rawSocket.pending || this._rawSocket.destroyed) {
+      return
+    }
+
+    return new Promise((resolve, reject) => {
+      const start = Date.now()
+
+      // Attempt to end the socket. If it takes longer to close than the
+      // timeout, destroy it manually.
+      const timeout = setTimeout(() => {
+        const cOpts = this._ma.toOptions()
+        log('Timeout closing socket to %s:%s after %dms, destroying it manually',
+          cOpts.host, cOpts.port, Date.now() - start)
+        this._rawSocket.destroy()
+        resolve()
+      }, opts.timeout || c.CLOSE_TIMEOUT)
+
+      this._rawSocket.once('close', () => clearTimeout(timeout))
+
+      this._rawSocket.end((err) => err ? reject(err) : resolve())
+    })
+  }
+
+  getObservedAddrs () {
+    return [this._ma]
+  }
+}
+
+module.exports = Libp2pSocket