[C#] Fix commit record pointer offset calculation (#912)

Co-authored-by: Alexander Solodov <[email protected]>

Author: asolodov

cs/src/core/FasterLog/FasterLogIterator.cs

@@ -379,7 +379,7 @@ public unsafe bool GetNext(MemoryPool<byte> pool, out IMemoryOwner<byte> entry,
                 if (isCommitRecord)
                 {
                     FasterLogRecoveryInfo info = new();
-                    info.Initialize(new BinaryReader(new UnmanagedMemoryStream((byte *)physicalAddress, entryLength)));
+                    info.Initialize(new BinaryReader(new UnmanagedMemoryStream((byte*) (headerSize + physicalAddress), entryLength)));
                     if (info.CommitNum != long.MaxValue) continue;
 
                     // Otherwise, no more entries
@@ -442,7 +442,7 @@ public unsafe bool TryConsumeNext<T>(T consumer) where T : ILogEntryConsumer
                 if (isCommitRecord)
                 {
                     FasterLogRecoveryInfo info = new();
-                    info.Initialize(new BinaryReader(new UnmanagedMemoryStream((byte *)physicalAddress, entryLength)));
+                    info.Initialize(new BinaryReader(new UnmanagedMemoryStream((byte*) (headerSize + physicalAddress), entryLength)));
                     if (info.CommitNum != long.MaxValue) continue;
 
                     // Otherwise, no more entries