Upon a showing that the attorney of record at the time of the defendant's first appearance in the court of record or a principal witness or a party in a criminal proceeding is a member of the legislature and that the legislature is in session or that a legislative interim committee of which the legislator is a member is meeting or is to meet within the next seven days, the defendant is entitled to a reasonable continuance of the date of trial until at least 15 days after the legislative session or interim committee meeting. However, a continuance for this reason shall not exceed 30 days after recess of the legislature or interim committee. A continuance may not be granted for any longer time than it is affirmatively proved the ends of justice require.