Add TCP write in binary mode

[tryhus]

I added a TCP write function to write raw binary data.

[sandeepmistry]

Hi @tryhus,

Thank you for opening this pull request, what is the advantage for this functionality?

Should write be updated to use this?

[tryhus]

Hi sandeepmistry,

Thank you for opening this pull request, what is the advantage for this functionality?

The current write function only allow to send char data.
Furthermore, according to the documentation "not all of the ASCII charset can be used".

It's not convient when you have to send values because you have to convert them to char what it's less accurate for float value and it takes more bytes (it can matter if you don't have many bytes/mounth within your contract).

For these reasons, in my application, I needed to send raw data from the MKR to a server.
So I thought someone else can be in the same situation.

Should write be updated to use this?

You mean write of ModemClass ?

[tryhus]

I added a function to wait TCP acknowledgement.
I also updated the previous function.

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