fix: improperly formed mime-type changed from binary to application/octet-stream (#21)

Co-authored-by: Alexandre Boccagny <[email protected]>

Author: aboccag

Diff for: RSocket.Core/RSocketOptions.cs

@@ -1,11 +1,11 @@
-using System;
+using System;
 
 namespace RSocket
 {
 	public class RSocketOptions
 	{
 		public const int INITIALDEFAULT = int.MinValue;
-		public const string BINARYMIMETYPE = "binary";
+		public const string BINARYMIMETYPE = "application/octet-stream";
 
 		public TimeSpan KeepAlive { get; set; }
 		public TimeSpan Lifetime { get; set; }
@@ -24,4 +24,4 @@ public class RSocketOptions
 			MetadataMimeType = BINARYMIMETYPE,
 		};
 	}
-}
+}