Incorporated reveiw comments

Author: Ron Petrusha

xml/System.Buffers/IMemoryOwner`1.xml

@@ -23,7 +23,7 @@
     <remarks>
       <format type="text/markdown"><![CDATA[  
 
-The `IMemoryOwner<T>` interface is used to define the owner responsible for the lifetime management of a <xref:System.Memory%601> buffer. An instance of the `IMemoryOwner<T>` interface is returned by the <xref:System.Buffers.ArrayPool%601.Rent%2A?displayProperty=nameWithType> and <xef:System.Buffers.MemoryPool%601.Rent%2A?displayProperty=nameWithType> methods. 
+The `IMemoryOwner<T>` interface is used to define the owner responsible for the lifetime management of a <xref:System.Memory%601> buffer. An instance of the `IMemoryOwner<T>` interface is returned by the <xref:System.Buffers.MemoryPool%601.Rent%2A?displayProperty=nameWithType> methods. 
 
 While a buffer can have multiple consumers, it can only have a single owner at any given time. The owner can:
 
@@ -33,6 +33,8 @@ While a buffer can have multiple consumers, it can only have a single owner at a
 
 - Destroy the buffer when it is no longer in use.
 
+Because the `IMemoryOwner<T>` object implements the <xref:System.IDisposable> interface, you should call its <xref:System.IDisposable.Dispose%2A> method only after the memory buffer is no longer needed and you have destroyed it. You should *not* dispose of the `IMemoryOnwer<T>` object while a reference to its memory is available. This means that the type in which `IMemoryOwner<T>` is declared should not have a <xref:System.Object.Finalize%2A> method.
+
    ]]></format>
 
     </remarks>

xml/System/Memory`1.xml

@@ -29,25 +29,14 @@
   
 ## Remarks  
   
-Like <xref:System.Span%601>, `Memory<T>` represents a contiguous region of memory. Unlike <xref:System.Span%601>, however, `Memory<T>` is not a [ref struct](~/doocs/csharp/reference-semantics-with-value-types?view=netcore-2.1.md#ref-struct-type). This means that `Memory<T>` can be backed by:
-
-- An array.
-- A string (a sequence of characters).
-- A <xref:System.Runtime.InteropServices.SafeHandle>.
-
-`Memory<T>` cannot be backed by transient unmanaged memory, such as memory available by using [stackalloc](~/docs/csharp/language-reference/keywords/stackalloc.md).
-
-Because the memory allocated to the `Memory<T>` structure is placed on the managed heap, it does not have the same restrictions as a <xref:System.Span%601> instance. In particular:
+Like <xref:System.Span%601>, `Memory<T>` represents a contiguous region of memory. Unlike <xref:System.Span%601>, however, `Memory<T>` is not a [ref struct](~/doocs/csharp/reference-semantics-with-value-types?view=netcore-2.1.md#ref-struct-type). This means that `Memory<T>` can be placed on the managed heap, whereas <xref:System.Span%601> cannot. As a result, the `Memory<T>` structure does not have the same restrictions as a <xref:System.Span%601> instance. In particular:
 
 - It can be used as a field in a class.
 
 - It can be used across `await` and `yield` boundaries.
 
 In addition to `Memory<T>`, you can use <xref:System.ReadOnlyMemory%601?displayProperty=nameWithType> to represent immutable or read-only memory.
 
-### Memory<T> basics
-
-
     ]]></format>
      </remarks>
   </Docs>
@@ -73,12 +62,17 @@ In addition to `Memory<T>`, you can use <xref:System.ReadOnlyMemory%601?displayP
        <remarks>
           <format type="text/markdown"><![CDATA[  
 
-If `array` is `null`, this constructor returns a `null` <xref:System.Memory%601> object.
+If `array` is `null`, this constructor returns a <xref:System.Memory%601> object with a `default<T>` value.
 
       ]]></format>
         </remarks>
         <exception cref="T:System.ArrayTypeMismatchException">
-          <paramref name="T" /> is a reference type, and <paramref name="array" /> is not an array of type <paramref name="T" />.</exception>
+          <paramref name="T" /> is a reference type, and <paramref name="array" /> is not an array of type <paramref name="T" />.
+        
+-or-
+
+The array is <see href="~/docs/csharp/programming-guide/concepts/covariance-contravariance/index.md" />covariant.</see>
+          </exception>
       </Docs>
     </Member>
     <Member MemberName=".ctor">
@@ -106,7 +100,7 @@ If `array` is `null`, this constructor returns a `null` <xref:System.Memory%601>
        <remarks>
           <format type="text/markdown"><![CDATA[  
 
-If `array` is `null`, this constructor returns a `null` <xref:System.Memory%601> object.
+If `array` is `null`, this constructor returns a  <xref:System.Memory%601> object with a `default<T>` value.
 
        ]]></format>
         </remarks>
@@ -201,7 +195,9 @@ The two objects are equal if:
    - `other` is a <xref:System.Memory%601> or <xref:System.ReadOnlyMemory%601> object.
    
    - Both objects point to the same array and have the same length.
-   
+
+The `Equals(Memory<T>)` method performs a test for reference equality; it does not compare the elements of <xref:Memory%601> for equality.
+
          ]]></format>
         </remarks>
       </Docs>
@@ -470,7 +466,7 @@ The garbage collector will not move the memory until the returned <xref:T:System
         <param name="start">The index at which to begin the slice.</param>
         <param name="length">The number of elements to include in the slice.</param>
         <summary>Forms a slice out of the current memory starting at a specified index for a specified length.</summary>
-        <returns>An object that <paramref name="length" /> elements from the current instance starting at <paramref name="start" />. </returns>
+        <returns>An object that contains <paramref name="length" /> elements from the current instance starting at <paramref name="start" />. </returns>
         <remarks>To be added.</remarks>
         <exception cref="T:System.ArgumentOutOfRangeExceptionException"><paramref name="start" /> is less than zero or greater than or equal to <see cref="P:Memory`1.Length" />.
 

xml/System/Span`1.xml

@@ -69,7 +69,7 @@ The following example creates a slice of the middle five elements of a 10-elemen
 
 ## Span\<T> and slices
 
-`Span\<T>` includes two overloads of the <xref:System.Span%601.Slice%2A> method that forms a slice out of the current span that starts at a specified index. This makes it possible to treat the data in a `Span\<T>` as a set of logical chunks that can be processed as needed by portions of a data processing pipeline with minimal performance impact. For example, since modern server protocols are often text-based, manipulation of strings and substrings is particularly important. In the <xref:System.String> class, the major method for extracting substrings is <xref:System.String.Substring%2A>. For data pipelines that rely on extensive string manipulation, it use offers some performance penalties, since it:
+`Span\<T>` includes two overloads of the <xref:System.Span%601.Slice%2A> method that forms a slice out of the current span that starts at a specified index. This makes it possible to treat the data in a `Span\<T>` as a set of logical chunks that can be processed as needed by portions of a data processing pipeline with minimal performance impact. For example, since modern server protocols are often text-based, manipulation of strings and substrings is particularly important. In the <xref:System.String> class, the major method for extracting substrings is <xref:System.String.Substring%2A>. For data pipelines that rely on extensive string manipulation, its use offers some performance penalties, since it:
 
 1. Creates a new string to hold the substring.