feat: derive Clone for HashBuilder (#72)

feat: derive Clone for HashBuilder

src/hash_builder/mod.rs

@@ -39,7 +39,7 @@ pub use value::{HashBuilderValue, HashBuilderValueRef};
 /// up, combining the hashes of child nodes and ultimately generating the root hash. The root hash
 /// can then be used to verify the integrity and authenticity of the trie's data by constructing and
 /// verifying Merkle proofs.
-#[derive(Debug, Default)]
+#[derive(Debug, Clone, Default)]
 #[allow(missing_docs)]
 pub struct HashBuilder {
     pub key: Nibbles,

src/proof/retainer.rs

@@ -6,7 +6,7 @@ use alloc::vec::Vec;
 
 /// Proof retainer is used to store proofs during merkle trie construction.
 /// It is intended to be used within the [`HashBuilder`](crate::HashBuilder).
-#[derive(Default, Debug)]
+#[derive(Default, Clone, Debug)]
 pub struct ProofRetainer {
     /// The nibbles of the target trie keys to retain proofs for.
     targets: Vec<Nibbles>,