code: func MerkleSize(leafCount uint64) uint64 {
  	var acc uint64 = 1
  
  	if leafCount < 2 {
  		return leafCount
  	}
  
  	for leafCount >= 2 {
  		acc += leafCount
  		leafCount = (leafCount + 1) >> 1
  	}
  	return acc
  }
docs: // MerkleSize computes the size of a merkle tree, e.g. its node number.
  // 	leafCount is the number of leaves of the tree