code: @Override
      @Synchronized
      public CompletableFuture<Map<String, StreamConfiguration>> listStreamsInScope(final String scopeName) {
          InMemoryScope inMemoryScope = scopes.get(scopeName);
          if (inMemoryScope != null) {
              return inMemoryScope.listStreamsInScope()
                      .thenApply(streams -> {
                          HashMap<String, StreamConfiguration> result = new HashMap<>();
                          for (String stream : streams) {
                              StreamConfiguration configuration = Futures.exceptionallyExpecting(
                                      getConfiguration(scopeName, stream, null, executor),
                                      e -> e instanceof StoreException.DataNotFoundException, null).join();
                              if (configuration != null) {
                                  result.put(stream, configuration);
                              }
                          }
                          return result;
                      });
          } else {
              return Futures.failedFuture(StoreException.create(StoreException.Type.DATA_NOT_FOUND, scopeName));
          }
      }
docs: List the streams in scope.
  
  @param scopeName Name of scope
  @return List of streams in scope