feat: add topology interfaces (#7)

* feat: topology

* feat: multicodec-topology

* chore: address review

Co-Authored-By: Jacob Heun <jacobheun@gmail.com>

* chore: remove error from disconnect

* docs: topology

* chore: apply suggestions from code review

Co-Authored-By: Jacob Heun <jacobheun@gmail.com>

test/topology/topology.spec.js

@@ -0,0 +1,26 @@
+/* eslint-env mocha */
+'use strict'
+
+const tests = require('../../src/topology/tests/topology')
+const Topology = require('../../src/topology')
+
+describe('topology compliance tests', () => {
+  tests({
+    setup (properties) {
+      const handlers = {
+        onConnect: () => { },
+        onDisconnect: () => { }
+      }
+
+      const topology = new Topology({
+        handlers,
+        ...properties
+      })
+
+      return topology
+    },
+    teardown () {
+      // cleanup resources created by setup()
+    }
+  })
+})