Fix memory pool metrics unit to follow standard

Author: JamesNK

src/Shared/Buffers.MemoryPool/PinnedBlockMemoryPoolMetrics.cs

@@ -23,22 +23,22 @@ public PinnedBlockMemoryPoolMetrics(IMeterFactory meterFactory)
 
         _currentMemory = _meter.CreateUpDownCounter<long>(
             "aspnetcore.memorypool.current_memory",
-            unit: "{bytes}",
+            unit: "By",
             description: "Number of bytes that are currently pooled by the pool.");
 
         _totalAllocatedMemory = _meter.CreateCounter<long>(
            "aspnetcore.memorypool.total_allocated",
-            unit: "{bytes}",
+            unit: "By",
             description: "Total number of allocations made by the pool.");
 
         _evictedMemory = _meter.CreateCounter<long>(
            "aspnetcore.memorypool.evicted_memory",
-            unit: "{bytes}",
+            unit: "By",
             description: "Total number of bytes that have been evicted.");
 
         _totalRented = _meter.CreateCounter<long>(
             "aspnetcore.memorypool.total_rented",
-            unit: "{bytes}",
+            unit: "By",
             description: "Total number of rented bytes from the pool.");
     }