ByteBuffer::__construct() behaviour is always surprising to one use case or the other

[dktapps]

If the caller wants to read a ByteBuffer for reading, the offset should be 0, so that the bytes can be read from the beginning. If the caller wants to write a ByteBuffer, the offset should be placed at the end of the input data, as if writeByteArray() was used.

Possible solutions:

• Make the offset parameter mandatory
• Make a parameter that indicates whether the offset should be at the beginning or the end (slightly easier to use than a mandatory offset parameter)
• Make the constructor private and have ::reader() and ::writer() static factory functions
• Split ByteBuffer into a ByteBufferReader and ByteBufferWriter
• Separate read offset and write offset (effectively what BinaryStream was implicitly doing)