Make it possible to stop payload building loop

[mattsse]

Describe the feature

currently the basic payload builder tries to build better and better blocks.

this makes sense for eth and op in sequencer mode but not for op if no txs from the pool should be included because then the block is predetermined:

reth/crates/optimism/payload/src/builder.rs

Lines 149 to 151 in b814770

	/// Payload attributes by the sequencer. If the `no_tx_pool` argument is passed in
	/// the payload attributes, the transaction pool will be ignored and the only transactions
	/// included in the payload will be those sent through the attributes.

but we still spawn new jobs in a loop:

reth/crates/payload/basic/src/lib.rs

Lines 405 to 411 in b814770

	// check if the interval is reached
	while this.interval.poll_tick(cx).is_ready() {
	// start a new job if there is no pending block and we haven't reached the deadline
	if this.pending_block.is_none() {
	this.spawn_build_job();
	}
	}

we need a way for the job to tell the builder to not schedule any more jobs.

we can do this by introducing a new outcome variant here:

reth/crates/payload/basic/src/lib.rs

Line 703 in b814770

Better {

this is something like

Freeze(Payload)

and then check before we spawn a new block if the payload is frozen

reth/crates/payload/basic/src/lib.rs

Lines 407 to 410 in b814770

	// start a new job if there is no pending block and we haven't reached the deadline
	if this.pending_block.is_none() {
	this.spawn_build_job();
	}

so we need a marker to track the state of:

reth/crates/payload/basic/src/lib.rs

Lines 324 to 325 in b814770

	/// The best payload so far.
	best_payload: Option<Builder::BuiltPayload>,

either a bool or an enum, like Either enum BestPayload {Frozen(),Current} or similar

Additional context

No response

[hoank101]

Hey sir, I'd like to work on this