Remove memory allocations in some hot paths

src/common/ring_buffer.h

@@ -9,6 +9,7 @@
 #include <cstddef>
 #include <cstring>
 #include <new>
+#include <span>
 #include <type_traits>
 #include <vector>
 
@@ -53,7 +54,7 @@ public:
         return push_count;
     }
 
-    std::size_t Push(const std::vector<T>& input) {
+    std::size_t Push(const std::span<T> input) {
         return Push(input.data(), input.size());
     }
 

src/common/scratch_buffer.h

@@ -3,6 +3,9 @@
 
 #pragma once
 
+#include <iterator>
+
+#include "common/concepts.h"
 #include "common/make_unique_for_overwrite.h"
 
 namespace Common {
@@ -16,6 +19,12 @@ namespace Common {
 template <typename T>
 class ScratchBuffer {
 public:
+    using iterator = T*;
+    using const_iterator = const T*;
+    using value_type = T;
+    using element_type = T;
+    using iterator_category = std::contiguous_iterator_tag;
+
     ScratchBuffer() = default;
 
     explicit ScratchBuffer(size_t initial_capacity)