code: ReadConcern getReadConcern() {
          ReadConcern readConcern = findOptions.getReadConcern();
          if (readConcern != null) {
              return readConcern;
          }
          return collection.getReadConcern();
      }
docs: Get the read concern for this collection.
  
  @return the {@link com.mongodb.ReadConcern}
  @since 3.2
  @mongodb.server.release 3.2
  @mongodb.driver.manual reference/readConcern/ Read Concern