diff --git a/raknet/BitStream.cpp b/raknet/BitStream.cpp
index 2eade3a..4e1c8ac 100644
--- a/raknet/BitStream.cpp
+++ b/raknet/BitStream.cpp
@@ -110,6 +110,15 @@ BitStream::BitStream( char* _dataC, unsigned int lengthInBytes, bool _copyData )
 		data = ( unsigned char* ) _data;
 }
 
+// Use this if you pass a pointer copy to the constructor (_copyData==false) and want to overallocate to prevent reallocation
+void BitStream::SetNumberOfBitsAllocated( const unsigned int lengthInBits )
+{
+#ifdef _DEBUG
+	assert( lengthInBits >= ( unsigned int ) numberOfBitsAllocated );
+#endif
+	numberOfBitsAllocated = lengthInBits;
+}
+
 BitStream::~BitStream()
 {
 	if ( copyData && numberOfBitsAllocated > BITSTREAM_STACK_ALLOCATION_SIZE << 3)
diff --git a/raknet/BitStream.h b/raknet/BitStream.h
index cf9bbe2..b5e3390 100644
--- a/raknet/BitStream.h
+++ b/raknet/BitStream.h
@@ -5,6 +5,7 @@
 
 #include "Export.h"
 #include "NetworkTypes.h"
+#include <assert.h>
 
 /// Arbitrary size, just picking something likely to be larger than most packets
 #define BITSTREAM_STACK_ALLOCATION_SIZE 256
@@ -46,6 +47,10 @@ namespace RakNet
 		/// Destructor 
 		~BitStream();
 
+		/// Use this if you pass a pointer copy to the constructor
+		/// *(_copyData==false) and want to overallocate to prevent
+		/// *reallocation
+		void SetNumberOfBitsAllocated( const unsigned int lengthInBits );
 
 
 	private: