format method
Writes a textual description of the state stree to the sink. The specific output format is
controlled by the type of the formatter.
void formatDOT(StateTreeBuilder treeBuilder) {
var sink = StringBuffer();
// Write the state tree Graphviz DOT format.
treeBuilder.format(sink, DotFormatter());
}
Implementation
void format(StringSink sink, StateTreeFormatter formatter) {
_validate();
formatter.formatTo(this, sink);
}