Removed bstream.Block.PreviousRef method

Its implementation was invalid since it was assuming that the previous number is always minus one the current block num which is not true on a lot of supported chains (Solana and NEAR for example).

CHANGELOG.md

@@ -5,7 +5,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Removed
+
+- **BREAKING** Removed `bstream.Block.PreviousRef` method as it was invalid since it was assuming that the previous number is always minus one the current block num which is not true on a lot of supported chains (Solana and NEAR for example).
+
 ### Added
+
 - Added FileSourceWithSecondaryBlocksStores Option to allow a fallback location
 - `.SetNearBlocksCount(count)` and `.Clone()` on `Tracker` object.
 - `Tracker` object to streamline queries about different targets (like network head, database lib, relayer blockstream head, whatever other BlockRef tags), ask the question about them being near one another (to select between live mode or catch-up mode).  Also streamlines the requests of a start block, with a bunch of different backend implementations that can answer to the questions regarding where to start.

block.go

@@ -196,14 +196,6 @@ func (b *Block) AsRef() BlockRef {
 	return NewBlockRef(b.Id, b.Number)
 }
 
-func (b *Block) PreviousRef() BlockRef {
-	if b == nil || b.Number == 0 || b.PreviousId == "" {
-		return BlockRefEmpty
-	}
-
-	return NewBlockRef(b.PreviousId, b.Number-1)
-}
-
 //func (b *Block) Payload() []byte {
 //	if b == nil {
 //		return nil