Insert Byte Element into array of bytes

I have following code that reads a binary file into array of bytes, after I
read the file i need to insert a space in fisrt element of array ,how can I
achieve this

System.IO.FileStream fs = new
System.IO.FileStream(fileName,System.IO.FileMode.O pen,System.IO.FileAccess.Read);
System.IO.BinaryReader br = new System.IO.BinaryReader(fs);
byte [] sysFile = {0};
while(br.Read() > 0)
{
sysFile = br.ReadBytes(Convert.ToInt32(fs.Length));
}
br.Close();

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