question: void writeExternal ( DataOutput out ) throws IOException { out . writeByte ( ZRULES ) ; out . writeInt ( standardTransitions . length ) ; for ( long trans : standardTransitions ) { writeEpochSec ( trans , out ) ; } for ( ZoneOffset offset : standardOffsets ) { writeOffset ( offset , out ) ; } out . writeInt ( savingsInstantTransitions . length ) ; for ( long trans : savingsInstantTransitions ) { writeEpochSec ( trans , out ) ; } for ( ZoneOffset offset : wallOffsets ) { writeOffset ( offset , out ) ; } out . writeByte ( lastRules . length ) ; for ( ZoneOffsetTransitionRule rule : lastRules ) { writeRule ( rule , out ) ; } }
target:  Writes the state to the stream.