Optimize ByteBufferFetcher, Prototype

[revonateB0T]

Close #1971

We will do following things in this CL

• Make ByteBuffer lazily extracted to okio Buffer, to avoid heap thrashing (Actually we should let okio Buffer take these byte[]'s ownership if it is a HeapByteBuffer, but seems it is not possible)
• Introduce ByteBufferMetadata , to allow ImageDecoder take it directly

[revonateB0T]

@colinrtwhite
Done, PTAL
Didn't let AnimatedImageDecoderDecoder use ByteBufferMetadata in case one pass a HeapByteBuffer

[colinrtwhite]

I think this file might have to be renamed to ImageSource.jvm.kt to avoid class name conflicts.

[revonateB0T]

Well, it doesn't have top-level functions/field, so will not have clash.

[revonateB0T]

@colinrtwhite
Aha, Btw ByteArrayFetcher could be optimized with the same method(lazy extraction)

coil/coil-core/src/commonMain/kotlin/coil3/fetch/ByteArrayFetcher.kt

Line 17 in 98541db

source = Buffer().apply { write(byteArray) },

But I decided not to optimize it as I think one use ByteArray to decode would not care performance