Writes a tree describing the internal state of the sorted set splay tree.
charmap is an object that notes which characters to use to draw
lines. By default, this is the TreeLog.unicodeRound property from the
tree-log module. TreeLog.unicodeSharp and TreeLog.ascii are
alternatives. The properties are:
callback is a customizable function for rendering each node of the tree.
By default, it just writes the value of the node. It accepts the node and
a writer functions. The write function produces the line on which the
node joins the tree, and each subsequent line. The writeAbove function
can write lines before the branch.
log and logger default to console.log and console. To write
the representation to an array instead, they can be array.push and
array.