A Readable is a source of bytes that can be read from an InputStream
A subtype of Writable, every Readable can be trivially used as a Writable by transferring the bytes from the InputStream to the OutputStream, but not every Writable is a Readable.
Note that the InputStream is only available inside the readBytesThrough, and
may be closed and cleaned up (along with any associated resources) once the
callback returns.
- Companion:
- object