function amf0encSArray(a) {
  logger.debug("Do strict array!");
  let buf = Buffer.alloc(5);
  buf.writeUInt8(0x0A, 0);
  buf.writeUInt32BE(a.length, 1);
  let i;
  for (i = 0; i < a.length; i++) {
    buf = Buffer.concat([buf, amf0EncodeOne(a[i])]);
  }
  return buf;
}
AMF0 Encode Strict Array
@param {Array} a Array
@returns {Buffer}