Further optimise zio.http.Body.FileBody.asStream code

[guizmaii]

Following #3215

[guizmaii]

Replacing ZStream.repeatZIOOption with ZStream.repeatZIOChunkOption allows us to remove the .flattenChunks

Anyway, repeatZIOOption is using repeatZIOChunkOption underneath:

[guizmaii]

@kyri-petrou Are we sure this ZIO.suspendSucceed and the ZIO.attempt(fs.close()) will be run on a blocking thread? 🤔

[guizmaii]

@kyri-petrou Funnily enough, if we were managing to find a way to write a recursive type in Scala,

1. we wouldn't need this ugly (_.map(_.map(_ -> read))
2. we could write this:

              type Read = Task[Option[(Chunk[Byte], Read)]]
              val read: Read =
                ZIO.suspendSucceed {
                  try {
                    val buffer = new Array[Byte](size)
                    val len    = fs.read(buffer)
                    if (len > 0) Exit.succeed(Some(Chunk.fromArray(buffer.slice(0, len) -> read)))
                    else Exit.none
                  } catch {
                    case e: Throwable => Exit.fail(e)
                  }
                }

              Exit.succeed {
                ZStream
                  .unfoldChunkZIO(read)(ZIO.identityFn)
                  .ensuring(ZIO.attempt(fs.close()).ignoreLogged)
              }

😍

[987Nabil]

I can imagine, that there is a nice way to do this for Scala 3. But I think we are unable to find a nice way for Scala 2