function findBatchQueryArg(_shim, _batch, _fnName, args) {
  const sql = (args[0] && args[0][0]) || ''
  return sql.query || sql
}
Given the arguments for Cassandra's `batch` method, this finds the first
query in the batch.

@param {object} _shim - shim for instrumentation
@param {Function} _batch - original batch function
@param {string} _fnName - the function name (batch)
@param {Array} args - original arguments passed to the batch function
@returns {string} The query for this batch request.