chore(op-payload-builder): Refactor optimism_payload into smaller, reusable functions (#10904)

crates/optimism/payload/src/lib.rs

@@ -15,6 +15,7 @@ pub mod builder;
 pub use builder::OptimismPayloadBuilder;
 pub mod error;
 pub mod payload;
+
 pub use payload::{
     OptimismBuiltPayload, OptimismPayloadAttributes, OptimismPayloadBuilderAttributes,
 };

crates/payload/builder/src/error.rs

@@ -14,6 +14,9 @@ pub enum PayloadBuilderError {
     /// An oneshot channels has been closed.
     #[error("sender has been dropped")]
     ChannelClosed,
+    /// Build cancelled
+    #[error("build outcome cancelled")]
+    BuildOutcomeCancelled,
     /// If there's no payload to resolve.
     #[error("missing payload")]
     MissingPayload,