diff --git a/EonaCat.Logger/EonaCatCoreLogger/FileLoggerProvider.cs b/EonaCat.Logger/EonaCatCoreLogger/FileLoggerProvider.cs
index af3b882..3c8bd05 100644
--- a/EonaCat.Logger/EonaCatCoreLogger/FileLoggerProvider.cs
+++ b/EonaCat.Logger/EonaCatCoreLogger/FileLoggerProvider.cs
@@ -256,13 +256,13 @@ public sealed class FileLoggerProvider : BatchingLoggerProvider, IDisposable
         const int maxBatch = 5000;
         int batchCount = 0;
 
-        // Rent a buffer
-        byte[] combined = ArrayPool<byte>.Shared.Rent(BufferSize);
+        // Start with a reasonably sized buffer from the pool
+        int estimatedSize = 1024 * 64; // 64KB starting buffer
+        byte[] combined = ArrayPool<byte>.Shared.Rent(estimatedSize);
         int pos = 0;
 
         while (queue.TryDequeue(out var msg) && batchCount < maxBatch)
         {
-            // Rotate file if date changed
             var msgDate = msg.Timestamp.UtcDateTime.Date;
             if (state.Date != msgDate)
             {
@@ -270,66 +270,68 @@ public sealed class FileLoggerProvider : BatchingLoggerProvider, IDisposable
                 RotateByDate(state, msgDate, string.Empty);
             }
 
-            var msgText = BuildMessage(msg);
-            int byteCount = Utf8.GetByteCount(msgText);
+            var messageString = BuildMessage(msg);
+            int requiredLength = Utf8.GetByteCount(messageString);
 
-            // Flush buffer if message won't fit
-            if (pos + byteCount > combined.Length)
+            // Grow buffer if needed
+            if (pos + requiredLength > combined.Length)
             {
-                await FlushBufferAsync(state).ConfigureAwait(false);
-                pos = 0;
+                int newSize = Math.Max(combined.Length * 2, pos + requiredLength);
+                byte[] newBuffer = ArrayPool<byte>.Shared.Rent(newSize);
+                Array.Copy(combined, 0, newBuffer, 0, pos);
+                ArrayPool<byte>.Shared.Return(combined);
+                combined = newBuffer;
             }
 
-            Utf8.GetBytes(msgText, 0, msgText.Length, combined, pos);
-            pos += byteCount;
+            // Write directly into combined buffer
+            pos += Utf8.GetBytes(messageString, 0, messageString.Length, combined, pos);
             batchCount++;
         }
 
         if (pos == 0)
         {
             ArrayPool<byte>.Shared.Return(combined);
-            return;
+            return; // nothing to write
         }
 
+        // If encryption is enabled, encrypt into a new array
         byte[] dataToWrite;
-
         if (_isEncryptionEnabled)
         {
-            // Encrypt creates a new array, old buffer cleared immediately
             dataToWrite = Encrypt(combined.AsSpan(0, pos).ToArray());
-            Array.Clear(combined, 0, pos);
         }
         else
         {
+            // No encryption: just use the pooled buffer slice directly
             dataToWrite = combined;
         }
 
         // Flush buffer if needed
-        if (state.BufferPosition + dataToWrite.Length > BufferSize)
+        if (state.BufferPosition + pos > BufferSize)
         {
             await FlushBufferAsync(state).ConfigureAwait(false);
         }
 
         // Rollover if file exceeds max size
-        if (_maxFileSize > 0 && state.Size + dataToWrite.Length > _maxFileSize)
+        if (_maxFileSize > 0 && state.Size + pos > _maxFileSize)
         {
             await FlushBufferAsync(state).ConfigureAwait(false);
             RollOverAndCompressOldest(state, string.Empty);
         }
 
-        // Copy into buffer
-        Array.Copy(dataToWrite, 0, state.Buffer, state.BufferPosition, dataToWrite.Length);
-        state.BufferPosition += dataToWrite.Length;
-        state.Size += dataToWrite.Length;
+        // Copy directly into the file buffer
+        Array.Copy(dataToWrite, 0, state.Buffer, state.BufferPosition, pos);
+        state.BufferPosition += pos;
+        state.Size += pos;
 
+        // Clear sensitive data
+        Array.Clear(dataToWrite, 0, pos);
+
+        // Return buffer if unencrypted
         if (!_isEncryptionEnabled)
         {
-            // return pooled buffer if not encrypted
             ArrayPool<byte>.Shared.Return(dataToWrite);
         }
-
-        // Clear encrypted array immediately
-        Array.Clear(dataToWrite, 0, dataToWrite.Length);
     }
 
     private async Task FlushBufferAsync(FileState state, CancellationToken token = default)