ChangeFeedProcessor: Removes eager stream expandability validation

Remove SetLength validation from WithInMemoryLeaseContainer. Non-expandable
stream errors will propagate naturally from ShutdownAsync when it tries to
write. Also reorders validation so state-check runs before stream inspection.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: kirankumarkolli

Microsoft.Azure.Cosmos/src/ChangeFeedProcessor/ChangeFeedProcessorBuilder.cs

@@ -258,28 +258,13 @@ public virtual ChangeFeedProcessorBuilder WithInMemoryLeaseContainer(MemoryStrea
                 throw new ArgumentNullException(nameof(leaseState));
             }
 
+            this.ValidateNoLeaseContainerConfigured();
+
             if (!leaseState.CanWrite)
             {
                 throw new ArgumentException("The lease state stream must be writable so that state can be persisted on shutdown.", nameof(leaseState));
             }
 
-            // Verify the stream is expandable. A MemoryStream created via
-            // new MemoryStream(byte[]) is writable but not expandable and will
-            // throw NotSupportedException when ShutdownAsync tries to resize it.
-            try
-            {
-                leaseState.SetLength(leaseState.Length);
-            }
-            catch (NotSupportedException)
-            {
-                throw new ArgumentException(
-                    "The lease state stream must be resizable. Use 'new MemoryStream()' and write bytes into it "
-                    + "instead of 'new MemoryStream(byte[])' to create a resizable stream.",
-                    nameof(leaseState));
-            }
-
-            this.ValidateNoLeaseContainerConfigured();
-
             if (string.IsNullOrEmpty(this.InstanceName))
             {
                 this.InstanceName = ChangeFeedProcessorBuilder.InMemoryDefaultHostName;

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/ChangeFeed/ChangeFeedProcessorBuilderTests.cs

@@ -551,24 +551,6 @@ public void WithInMemoryLeaseContainerWithCorruptedStreamThrowsInvalidOperation(
             Assert.IsNotNull(ex.InnerException);
         }
 
-        [TestMethod]
-        public void WithInMemoryLeaseContainerWithNonResizableStreamThrows()
-        {
-            // new MemoryStream(byte[]) creates a writable but non-expandable stream
-            byte[] data = System.Text.Encoding.UTF8.GetBytes("[]");
-            MemoryStream nonResizableStream = new MemoryStream(data);
-
-            ChangeFeedProcessorBuilder builder = new ChangeFeedProcessorBuilder("workflowName",
-                ChangeFeedProcessorBuilderTests.GetMockedContainer(),
-                ChangeFeedProcessorBuilderTests.GetMockedProcessor(),
-                ChangeFeedProcessorBuilderTests.GetEmptyInitialization());
-
-            ArgumentException ex = Assert.ThrowsException<ArgumentException>(
-                () => builder.WithInMemoryLeaseContainer(nonResizableStream));
-
-            Assert.IsTrue(ex.Message.Contains("resizable"));
-        }
-
         #endregion
 
         private static ContainerInternal GetMockedContainer(string containerName = null)