add more docs

src/SharpCompress/IO/SharpCompressStream.Create.cs

@@ -7,13 +7,66 @@ namespace SharpCompress.IO;
 public partial class SharpCompressStream
 {
     /// <summary>
-    /// Creates a SharpCompressStream that acts as a passthrough wrapper.
-    /// No buffering is performed; CanSeek delegates to the underlying stream.
-    /// The underlying stream will not be disposed when this stream is disposed.
+    /// Creates a <see cref="SharpCompressStream"/> that acts as a zero-overhead passthrough wrapper
+    /// around <paramref name="stream"/> without taking ownership of it.
     /// </summary>
+    /// <remarks>
+    /// <para>
+    /// This is a thin wrapper: all reads, writes, and seeks are forwarded directly to the underlying
+    /// stream with no ring-buffer overhead. <see cref="Stream.CanSeek"/> delegates to the underlying
+    /// stream's own value.
+    /// </para>
+    /// <para>
+    /// The resulting stream does <b>not</b> support <see cref="StartRecording"/>, <see cref="Rewind()"/>,
+    /// or <see cref="StopRecording"/>. Call <see cref="Create"/> on the passthrough stream to obtain
+    /// a recording-capable wrapper when needed.
+    /// </para>
+    /// <para>
+    /// Because the stream does not take ownership, the underlying stream is <b>never</b> disposed when
+    /// this wrapper is disposed. Use this when you need to satisfy an API that expects a
+    /// <see cref="SharpCompressStream"/> without transferring lifetime responsibility.
+    /// </para>
+    /// </remarks>
+    /// <param name="stream">The underlying stream to wrap. Must not be <see langword="null"/>.</param>
+    /// <returns>
+    /// A passthrough <see cref="SharpCompressStream"/> that does not dispose <paramref name="stream"/>.
+    /// </returns>
     public static SharpCompressStream CreateNonDisposing(Stream stream) =>
         new(stream, leaveStreamOpen: true, passthrough: true, bufferSize: null);
 
+    /// <summary>
+    /// Creates a <see cref="SharpCompressStream"/> that supports recording and rewinding over
+    /// <paramref name="stream"/>, choosing the most efficient strategy based on the stream's
+    /// capabilities.
+    /// </summary>
+    /// <remarks>
+    /// <para><b>Seekable streams</b> — wraps in a thin delegate that calls the underlying
+    /// stream's native <see cref="Stream.Seek"/> directly. No ring buffer is allocated.
+    /// <see cref="StartRecording"/> stores the current position; <see cref="Rewind()"/> seeks
+    /// back to it.</para>
+    /// <para><b>Non-seekable streams</b> (network streams, compressed streams, pipes) — allocates
+    /// a ring buffer of <paramref name="bufferSize"/> bytes. All bytes read from the underlying
+    /// stream are kept in the ring buffer so that <see cref="Rewind()"/> can replay them without
+    /// re-reading the underlying stream. If more bytes have been read than the ring buffer can hold,
+    /// a subsequent rewind will throw <see cref="InvalidOperationException"/>; increase
+    /// <paramref name="bufferSize"/> or <see cref="Common.Constants.RewindableBufferSize"/> to
+    /// avoid this.</para>
+    /// <para><b>Already-wrapped streams</b> — if <paramref name="stream"/> is already a
+    /// <see cref="SharpCompressStream"/> (or a stack that contains one), it is returned as-is to
+    /// prevent double-wrapping and double-buffering.</para>
+    /// </remarks>
+    /// <param name="stream">The underlying stream to wrap. Must not be <see langword="null"/>.</param>
+    /// <param name="bufferSize">
+    /// Size in bytes of the ring buffer allocated for non-seekable streams.
+    /// Defaults to <see cref="Common.Constants.RewindableBufferSize"/> (81 920 bytes) when
+    /// <see langword="null"/>. Has no effect when <paramref name="stream"/> is seekable, because
+    /// no ring buffer is needed in that case.
+    /// </param>
+    /// <returns>
+    /// A <see cref="SharpCompressStream"/> wrapping <paramref name="stream"/>. The returned instance
+    /// owns the stream and will dispose it unless the original source was a non-disposing passthrough
+    /// wrapper.
+    /// </returns>
     public static SharpCompressStream Create(Stream stream, int? bufferSize = null)
     {
         var rewindableBufferSize = bufferSize ?? Constants.RewindableBufferSize;