Writes data from a specified range in a List<int> to the socket.
Writes into the socket from a List<int>. If start is present, the bytes
will be written to the socket starting from index start. If start is
not present, the bytes will be written starting from index 0. If end is
present, the end - start bytes will be written into the socket starting
at index start. If end is not provided, buffer.length elements will
be written to the socket starting from index start. If end == start,
nothing happens.
Source
void writeFromSync(List<int> buffer, [int start = 0, int end]);