add connection monitoring

client/lib/patch-db.ts

@@ -1,4 +1,4 @@
-import { merge, Observable, of } from 'rxjs'
+import { Observable } from 'rxjs'
 import { concatMap, finalize, map, tap } from 'rxjs/operators'
 import { Source } from './source/source'
 import { Store } from './store'
@@ -7,6 +7,7 @@ export { Operation } from 'fast-json-patch'
 
 export class PatchDB<T extends object> {
   store: Store<T>
+  connectionStatus$ = this.source.connectionStatus$
 
   constructor (
     private readonly source: Source<T>,
@@ -21,7 +22,7 @@ export class PatchDB<T extends object> {
     const sequence$ = this.store.watchAll$().pipe(map(cache => cache.sequence))
     // nested concatMaps, as it is written, ensure sync is not run for update2 until handleSyncResult is complete for update1.
     // flat concatMaps would allow many syncs to run while handleSyncResult was hanging. We can consider such an idea if performance requires it.
-    return merge(this.source.watch$(sequence$)).pipe(
+    return this.source.watch$(sequence$).pipe(
       tap(update => console.log('PATCHDB - source updated:', update)),
       concatMap(update => this.store.update$(update)),
       finalize(() => {