code: public UpdateIfMatchResult updateIfMatch(final V value, final String eTag) {
          return updateIfMatch(value, eTag, mongoProperties.getDefaultWriteTimeout(), TimeUnit.MILLISECONDS);
      }
docs: Updates the document if the document's ETAG is matching the given etag (conditional put).
  <p>
  Using this method requires that the document contains an "etag" field that is updated if
  the document is changed.
  </p>
  
  @param value the new value
  @param eTag  the etag used for conditional update
  @return {@link UpdateIfMatchResult}