Function write_pack_for_push 

pub fn write_pack_for_push(
    odb: &Odb,
    wants: &[ObjectId],
    haves: &[ObjectId],
    opts: &PackBuildOptions,
    w: &mut dyn Write,
) -> Result<PackStats>

Stream the pack a push sends to w: the objects reachable from wants but not from haves, bounded by the have tips as in build_pack_for_push.

Memory stays bounded by the object list rather than the pack size: on-disk deltas and whole objects are copied from the source packs batch by batch, and every phase shares one mapping of each source pack.

Parameters

• odb: the object database the objects are read from.
• wants: the new tips the remote should end up with.
• haves: objects the remote already holds (its tips and .haves), all present in odb.
• opts: delta, thin-pack and offset-delta settings for the remote.
• w: where the PACK v2 stream, trailer included, is written.

Returns

Object and byte counts of the pack written.

Errors

Missing wants, corrupt objects, or Error::Io when writing to w fails.