Fix IPC transport bug: Use write_all to send data over socket

[Bobface]

Data is sent over the IPC socket using .write() on a UnixStream. On success this method returns the number of bytes written as integer. This number is not handled however, the result is only checked for success.

Documentation for write() (highlighted important parts):

Writes a buffer into this writer, returning how many bytes were written.

This function will attempt to write the entire contents of buf, but the entire write may not succeed, or the write may also generate an error. A call to write represents at most one attempt to write to any wrapped object.

This seems to rarely be an issue with "normal" usage of web3-rs, since the messages sent over the socket are relatively small, a few hundred bytes at maximum. This seems to always fully succeed.

Just recently however, I started sending larger requests to my Ethereum node via an IPC socket and began hitting a bug where the node would randomly close the connection due to JSON parsing errors. After some debugging, it turns out that when sending large messages, they might not be sent in full due to not handling the return value of write().

This PR fixes this bug by replacing .write() with .write_all():

Attempts to write an entire buffer into this writer.

This method will continuously call write until there is no more data to be written. This method will not return until the entire buffer has been successfully written or such an error occurs. The first error generated from this method will be returned.

[Bobface]

Pinging this, should be a quick fix :).