Problem emitting binary files

Hi.
I am using this library, version 2 (socketIO-client 2).
I had trouble emitting binary files in chunks. this is the code:

```
progress = 0
dumpSize = os.stat(s_dummyDumpPath).st_size
dumpFile = open(s_dummyDumpPath, "r+b")
while True:
piece = dumpFile.read(1024)
if not piece:
# Sending finish message to server
serverSocket.emit(s_fileSendFin, { })
break
progress += len(piece)
serverSocket.emit(s_fileReq, {"name": s_dummyDumpName,"progress": progress * 100 / dumpSize, "buffer": piece})
f.close()
```

And I get the following error:

```
Traceback (most recent call last):
File "CTedAgent.py", line 40, in
serverSocket.emit(s_fileReq, {"name": s_dummyDumpName,"progress": progress * 100 / dumpSize, "buffer": piece})
File "/home/toml/.local/lib/python2.7/site-packages/socketIO_client/__init__.py", line 413, in emit
self._message(str(socketIO_packet_type) + socketIO_packet_data)
File "/home/toml/.local/lib/python2.7/site-packages/socketIO_client/__init__.py", line 26, in wrap
return f(*args, **kw)
File "/home/toml/.local/lib/python2.7/site-packages/socketIO_client/__init__.py", line 208, in _message
transport.send_packet(engineIO_packet_type, engineIO_packet_data)
File "/home/toml/.local/lib/python2.7/site-packages/socketIO_client/transports.py", line 161, in send_packet
packet = format_packet_text(engineIO_packet_type, engineIO_packet_data)
File "/home/toml/.local/lib/python2.7/site-packages/socketIO_client/parsers.py", line 170, in format_packet_text
return encode_string(str(packet_type) + packet_data)
File "/home/toml/.local/lib/python2.7/site-packages/socketIO_client/symmetries.py", line 32, in encode_string
return x.encode('utf-8')
UnicodeDecodeError: 'ascii' codec can't decode byte 0x90 in position 30: ordinal not in range(128)
```

Couldn't find any answer over the web :(