pub type Tree = [i8];Expand description
A tree specification: an array of i8 branch entries (RFC 6386 §8.1).
Each even index is an interior node; entry i and i + 1 are its 0 (left) and 1 (right)
branches. A positive entry is the index of a deeper interior node; a non-positive entry v is a
leaf whose value is -v. The associated interior-node probabilities are indexed by i >> 1.