Method that can be used for efficient type detection
when using stream abstraction for traversing nodes.
Will return the first
stream event would produce (for most nodes there is just
one token but for structured/container types multiple)
Returns code that identifies type of underlying numeric
value, if (and only if) node is a number node.
Method called to serialize node instances using given generator.
Type information is needed, even if JsonNode instances are "plain" JSON,
since they may be mixed with other types.