code: function concatBuffers(buffers) {
      var total, cur = 0, buf;
  
      // First we calculate the total length,
      total = buffers.reduce(function (tot, b) {
          return tot + b.length;
      }, 0);
  
      // then we allocate a new Buffer large enough to contain all data,
      buf = new Buffer(total);
      buffers.forEach(function (buffer) {
          // finally we copy the data into the new larger buffer.
          buffer.copy(buf, cur, 0);
          cur += buffer.length;
      });
  
      return buf;
  }
docs: Private helper functions ---- Concatenate several buffers to one.