code: func NewPSTMTPlanCacheKey(sessionVars *variable.SessionVars, pstmtID uint32, schemaVersion int64) kvcache.Key {
  	timezoneOffset := 0
  	if sessionVars.TimeZone != nil {
  		_, timezoneOffset = time.Now().In(sessionVars.TimeZone).Zone()
  	}
  	return &pstmtPlanCacheKey{
  		database:       sessionVars.CurrentDB,
  		connID:         sessionVars.ConnectionID,
  		pstmtID:        pstmtID,
  		snapshot:       sessionVars.SnapshotTS,
  		schemaVersion:  schemaVersion,
  		sqlMode:        sessionVars.SQLMode,
  		timezoneOffset: timezoneOffset,
  	}
  }
docs: // NewPSTMTPlanCacheKey creates a new pstmtPlanCacheKey object.