blob packing exception

[ibobalo]

Describe the bug
client send_message raise exception when sending blobs

To Reproduce
OSCClient(b'localhost', 10000).send_message(b'/my_uuid', [bytearray(range(16)),])

Expected behavior
16 bytes blob sent to server

Logs/output
Traceback (most recent call last):
File "", line 1, in
File "C:\Utils\Python3\lib\site-packages\oscpy\client.py", line 136, in send_message
stats = send_message(
File "C:\Utils\Python3\lib\site-packages\oscpy\client.py", line 63, in send_message
message, stats = format_message(
File "C:\Utils\Python3\lib\site-packages\oscpy\parser.py", line 271, in format_message
message = pack(
struct.error: pack expected 26 items for packing (got 3)

Platform (please complete the following information):

• OS: windows 10
• Python 3.7
• release

Additional context
THE REASON
WRITERS = (
...
(bytearray, (b'b', b'%ib')),
mean
struct.pack(b'16b', bytearray(range(16))) # it is not valid
struct.error: pack expected 16 items for packing (got 1)

FIX
it shoulfd be:
struct.pack(b'16s', bytearray(range(16)))
so,
WRITERS = (
...
(bytearray, (b's', b'%ib')),