code: public final ListSessionsPagedResponse listSessions(String database) {
      ListSessionsRequest request = ListSessionsRequest.newBuilder().setDatabase(database).build();
      return listSessions(request);
    }
docs: Lists all sessions in a given database.
  
  <p>Sample code:
  
  <pre><code>
  try (SpannerClient spannerClient = SpannerClient.create()) {
  String formattedDatabase = DatabaseName.format("[PROJECT]", "[INSTANCE]", "[DATABASE]");
  for (Session element : spannerClient.listSessions(formattedDatabase).iterateAll()) {
  // doThingsWith(element);
  }
  }
  </code></pre>
  
  @param database Required. The database in which to list sessions.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails