code: func (r *Reader) Find(key []byte, filtered bool, ro *opt.ReadOptions) (rkey, value []byte, err error) {
  	return r.find(key, filtered, ro, false)
  }
docs: // Find finds key/value pair whose key is greater than or equal to the
  // given key. It returns ErrNotFound if the table doesn't contain
  // such pair.
  // If filtered is true then the nearest 'block' will be checked against
  // 'filter data' (if present) and will immediately return ErrNotFound if
  // 'filter data' indicates that such pair doesn't exist.
  //
  // The caller may modify the contents of the returned slice as it is its
  // own copy.
  // It is safe to modify the contents of the argument after Find returns.