trie: make fullnode children hash calculation concurrently (#15131)

* trie: make fullnode children hash calculation concurrently

* trie: thread out only on topmost fullnode

* trie: clean up full node children hash calculation

* trie: minor code fixups

1 files changed, 4 insertions, 4 deletions

diff --git a/trie/secure_trie.go b/trie/secure_trie.go
index 20c303f31..1fde45165 100644
--- a/trie/secure_trie.go
+++ b/trie/secure_trie.go
@@ -199,10 +199,10 @@ func (t *SecureTrie) secKey(key []byte) []byte {
 // invalid on the next call to hashKey or secKey.
 func (t *SecureTrie) hashKey(key []byte) []byte {
 	h := newHasher(0, 0)
-	h.sha.Reset()
-	h.sha.Write(key)
-	buf := h.sha.Sum(t.hashKeyBuf[:0])
-	returnHasherToPool(h)
+	calculator := h.newCalculator()
+	calculator.sha.Write(key)
+	buf := calculator.sha.Sum(t.hashKeyBuf[:0])
+	h.returnCalculator(calculator)
 	return buf
 }