BUGFIX: Chunked file could get corrupted on overflow
BUGFIX: Chunked file could get corrupted on overflow

When Write() got a buffer with size that exceeded the buffer position,
new iteration bytes were incorrectly read from source buffer.

patchkit-net/patchkit-patcher-unity,genail/patchkit-patcher-unity,patchkit-net/patchkit-patcher-unity,mohsansaleem/patchkit-patcher-unity,patchkit-net/patchkit-patcher-unity,mohsansaleem/patchkit-patcher-unity,patchkit-net/patchkit-patcher-unity