Shared exchange functionality (#214)

CryptoExchange.Net/SharedApis/Interfaces/Rest/Futures/ILeverageRestClient.cs

@@ -0,0 +1,39 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace CryptoExchange.Net.SharedApis
+{
+    /// <summary>
+    /// Client for managing the leverage of a symbol
+    /// </summary>
+    public interface ILeverageRestClient : ISharedClient
+    {
+        /// <summary>
+        /// How the leverage setting is configured on the exchange
+        /// </summary>
+        SharedLeverageSettingMode LeverageSettingType { get; }
+
+        /// <summary>
+        /// Leverage request options
+        /// </summary>
+        EndpointOptions<GetLeverageRequest> GetLeverageOptions { get; }
+        /// <summary>
+        /// Get the current leverage setting for a symbol
+        /// </summary>
+        /// <param name="request">Request info</param>
+        /// <param name="ct">Cancellation token</param>
+        Task<ExchangeWebResult<SharedLeverage>> GetLeverageAsync(GetLeverageRequest request, CancellationToken ct = default);
+
+        /// <summary>
+        /// Leverage set request options
+        /// </summary>
+        SetLeverageOptions SetLeverageOptions { get; }
+        /// <summary>
+        /// Set the leverage for a symbol
+        /// </summary>
+        /// <param name="request">Request info</param>
+        /// <param name="ct">Cancellation token</param>
+        Task<ExchangeWebResult<SharedLeverage>> SetLeverageAsync(SetLeverageRequest request, CancellationToken ct = default);
+
+    }
+}