code: function (ndefRecords) {
  
          var encoded = [],
              tnf_byte,
              record_type,
              payload_length,
              id_length,
              i,
              mb, me, // messageBegin, messageEnd
              cf = false, // chunkFlag TODO implement
              sr, // boolean shortRecord
              il; // boolean idLengthFieldIsPresent
  
          for(i = 0; i < ndefRecords.length; i++) {
  
              mb = (i === 0);
              me = (i === (ndefRecords.length - 1));
              sr = (ndefRecords[i].payload.length < 0xFF);
              il = (ndefRecords[i].id.length > 0);
              tnf_byte = ndef.encodeTnf(mb, me, cf, sr, il, ndefRecords[i].tnf);
              encoded.push(tnf_byte);
  
              // type is stored as String, converting to bytes for storage
              record_type = util.stringToBytes(ndefRecords[i].type);
              encoded.push(record_type.length);
  
              if (sr) {
                  payload_length = ndefRecords[i].payload.length;
                  encoded.push(payload_length);
              } else {
                  payload_length = ndefRecords[i].payload.length;
                  // 4 bytes
                  encoded.push((payload_length >> 24));
                  encoded.push((payload_length >> 16));
                  encoded.push((payload_length >> 8));
                  encoded.push((payload_length & 0xFF));
              }
  
              if (il) {
                  id_length = ndefRecords[i].id.length;
                  encoded.push(id_length);
              }
  
              encoded = encoded.concat(record_type);
  
              if (il) {
                  encoded = encoded.concat(ndefRecords[i].id);
              }
  
              encoded = encoded.concat(ndefRecords[i].payload);
          }
  
          return encoded;
      }
docs: Encodes an NDEF Message into bytes that can be written to a NFC tag.
  
  @ndefRecords an Array of NDEF Records
  
  @returns byte array
  
  @see NFC Data Exchange Format (NDEF) http://www.nfc-forum.org/specs/spec_list/