Make Noop process type stable (#174)

Author: nhz2

src/noop.jl

@@ -132,7 +132,7 @@ initial_output_size(codec::Noop, input::Memory) = length(input)
 
 function process(codec::Noop, input::Memory, output::Memory, error::Error)
     iszero(length(input)) && return (0, 0, :end)
-    n = min(length(input), length(output))
+    n::Int = min(length(input), length(output))
     unsafe_copyto!(output.ptr, input.ptr, n)
     (n, n, :ok)
 end