move and tweak comment

src/v0.rs

@@ -821,8 +821,6 @@ pub fn serialize<W:BinWriterExt>(block:&Block,writer:&mut W)->Result<(),binrw::E
 		None
 	}
 
-	// plan events into segments without spilling over max size threshold
-	// each index describes the non-inclusive end index of the range of events included in the block.
 	struct PlannedBlock{
 		// index is not the same as BlockId.
 		// It is list-local for both plan_offline and plan_realtime.
@@ -830,6 +828,8 @@ pub fn serialize<W:BinWriterExt>(block:&Block,writer:&mut W)->Result<(),binrw::E
 		time:f64,
 		plan:Plan<Range<usize>>,
 	}
+	// plan events into segments without spilling over max size threshold
+	// each plan describes the range of events included in the block.
 	let mut plan_offline=std::collections::VecDeque::new();
 	{
 		let mut plan=Plan::default();