zero-copy ByteArray to Buffer for reading purpose

[Chuckame]

Context

I'm currently the maintainer of avro4k and I'm planning to use okio for kicking out java streams and hoping a day to be multiplatform.

A lot of apps/libs/frameworks are dealing only with ByteArray (I'm not saying it's a good idea though). On our side, in the avro world, and especially in the messaging world (kafka, rabbitmq, ...) everything is using a ByteArray and we have no room for improvement to use ByteBuffer or even okio's Buffer.

We can encode easily data to a Buffer then reading the content to a ByteArray.

But for decoding from a ByteArray, with okio, we only have to choice to first copy the content to a Buffer and then decode, that is really bad regarding performances.

By the way, we are not using directly Buffer but BufferedSink and BufferedSource for this really great encoding/decoding API, but sadly those interfaces are sealed.

Proposal

A constructor of BufferedSource that takes a ByteArray to allow reading "complex" values (readLongLe, readUtf8, ...) over a ByteArray

Non goal

Backing a Buffer with a ByteArray : https://github.com/square/okio/issues/1360