§ 703-a. Employment of stenographer. Whenever the district attorney of any county in the performance of his duties shall be required to prosecute a contested criminal proceeding before a magistrate of a town or village, unless pursuant to law a stenographer be regularly employed by such magistrate or in the court over which he presides, said district attorney may employ a stenographer to take the testimony on such trial. The board of supervisors of each county shall fix the rate of compensation to be paid to such stenographer for such services rendered; and in addition thereto such stenographer shall be entitled to and shall be allowed for a copy of testimony furnished to the district attorney the same rate per folio as is now allowed to the stenographers of the county court in their respective counties, and such stenographer shall receive the same compensation for all copies of the evidence in excess of three copies furnished by him to the district attorney. Such compensation shall be a county charge, and shall be audited and paid upon the affidavit of the stenographer and the certificate of the district attorney specifying the number of days of actual service and the number of folios furnished.