Hedging: Adds Read hedging PREVIEW contracts

Microsoft.Azure.Cosmos/src/CosmosClientOptions.cs

@@ -694,7 +694,12 @@ public Func<HttpClient> HttpClientFactory
         /// <summary>
         /// Availability Strategy to be used for periods of high latency
         /// </summary>
-        internal AvailabilityStrategy AvailabilityStrategy { get; set; }
+#if PREVIEW
+        public
+#else
+        internal
+#endif
+        AvailabilityStrategy AvailabilityStrategy { get; set; }
 
         /// <summary>
         /// Enable partition key level failover

Microsoft.Azure.Cosmos/src/Fluent/CosmosClientBuilder.cs

@@ -705,7 +705,12 @@ internal CosmosClientBuilder WithApiType(ApiType apiType)
         /// </summary>
         /// <param name="strategy"></param>
         /// <returns>The CosmosClientBuilder</returns>
-        internal CosmosClientBuilder WithAvailibilityStrategy(AvailabilityStrategy strategy)
+#if PREVIEW
+        public
+#else
+        internal
+#endif
+        CosmosClientBuilder WithAvailibilityStrategy(AvailabilityStrategy strategy)
         {
             this.clientOptions.AvailabilityStrategy = strategy;
             return this;

Microsoft.Azure.Cosmos/src/RequestOptions/RequestOptions.cs

@@ -76,7 +76,12 @@ public class RequestOptions
         /// reduce latency and increase availability. Currently there is one type of availability strategy, parallel request hedging.
         /// If there is a globally enabled availability strategy, setting one in the request options will override the global one.
         /// </summary>
-        internal AvailabilityStrategy AvailabilityStrategy { get; set; }
+#if PREVIEW
+        public
+#else
+        internal
+#endif
+        AvailabilityStrategy AvailabilityStrategy { get; set; }
 
         /// <summary>
         /// Gets or sets the boolean to use effective partition key routing in the cosmos db request.

Microsoft.Azure.Cosmos/src/Routing/AvailabilityStrategy/AvailabilityStrategy.cs

@@ -11,7 +11,12 @@ namespace Microsoft.Azure.Cosmos
     /// <summary>
     /// Types of availability strategies supported
     /// </summary>
-    internal abstract class AvailabilityStrategy
+#if PREVIEW
+    public
+#else
+    internal
+#endif
+    abstract class AvailabilityStrategy
     {
         /// <summary>
         /// Execute the availability strategy
@@ -27,6 +32,10 @@ public abstract Task<ResponseMessage> ExecuteAvailabilityStrategyAsync(
             RequestMessage requestMessage,
             CancellationToken cancellationToken);
 
-        internal abstract bool Enabled();
+        /// <summary>
+        /// Checks to see if the strategy is enabled
+        /// </summary>
+        /// <returns>a bool representing if the strategy is enabled</returns>
+        public abstract bool Enabled();
     }
 }

Microsoft.Azure.Cosmos/src/Routing/AvailabilityStrategy/CrossRegionParallelHedgingAvailabilityStrategy.cs

@@ -21,7 +21,12 @@ namespace Microsoft.Azure.Cosmos
     /// if the first parallel request or the original has not returned after the step time, 
     /// additional parallel requests will be sent out there is a response or all regions are exausted.
     /// </summary>
-    internal class CrossRegionParallelHedgingAvailabilityStrategy : AvailabilityStrategy
+#if PREVIEW
+    public
+#else
+    internal
+#endif
+    class CrossRegionParallelHedgingAvailabilityStrategy : AvailabilityStrategy
     {
         private const string HedgeContext = "Hedge Context";
         private const string ResponseRegion = "Response Region";
@@ -59,7 +64,11 @@ public CrossRegionParallelHedgingAvailabilityStrategy(
             this.ThresholdStep = thresholdStep ?? TimeSpan.FromMilliseconds(-1);
         }
 
-        internal override bool Enabled()
+        /// <summary>
+        /// Checks to see if the strategy is enabled
+        /// </summary>
+        /// <returns>a bool representing if the strategy is enabled</returns>
+        public override bool Enabled()
         {
             return true;
         }

Microsoft.Azure.Cosmos/src/Routing/AvailabilityStrategy/DisabledAvailabilityStrategy.cs

@@ -10,9 +10,18 @@ namespace Microsoft.Azure.Cosmos
     /// <summary>
     /// A Disabled availability strategy that does not do anything. Used for overriding the default global availability strategy.
     /// </summary>
-    internal class DisabledAvailabilityStrategy : AvailabilityStrategy
+#if PREVIEW
+    public
+#else
+    internal
+#endif
+    class DisabledAvailabilityStrategy : AvailabilityStrategy
     {
-        internal override bool Enabled()
+        /// <summary>
+        /// Checks to see if the strategy is enabled
+        /// </summary>
+        /// <returns>a bool representing if the strategy is enabled, will always be false</returns>
+        public override bool Enabled()
         {
             return false;
         }