Get next parsing event - element content wil be coalesced and only one
TEXT event must be returned for whole element content
(comments and processing instructions will be ignored and emtity references
must be expanded or exception mus be thrown if entity reerence can not be exapnded).
If current event is START_TAG then if next element is TEXT then element content is returned
or if next event is END_TAG then empty string is returned, otherwise exception is thrown.
This method works similarly to next() but will expose
additional event types (COMMENT, CDSECT, DOCDECL, ENTITY_REF, PROCESSING_INSTRUCTION, or
IGNORABLE_WHITESPACE) if they are available in input.