rework the block context to take a mutable ref to the batch

[garyyu]

To track an improvement item here, the original discussion: #3004 (comment)

garyyu 2 days ago Member
But I would still prefer ONE batch here, because one commit() is twice efficient than two commit() :-)

@antiochp
antiochp 2 days ago •
Author Member
We create two separate block contexts and these both take ownership of the batch, so we can't reuse the same one.

We need to rework the block context to take a mutable ref to the batch. Pretty sure this is possible but the code gets tricky because of the lifetimes involved.
Maybe tackle this in a separate PR.

[garyyu]

@garyyu I assigned this to you if you don't mind :-)

[antiochp]

Lets leave this open for a bit to remind us (but reserving the right to close it out unfixed...)
I'm not a huge fan of tracking too much "work in progress" - particularly if it just sits and is not actively worked on. If this is important we will pick it up at a later date regardless of whether its tracked by an issue like this.