it is difficult for me to understand the bitshares tookit serialization mechanism and technology, would be appreciated if anyone can provide some guidence /documentation
Sure... 100% of all serialization is managed by fc via the reflection system.
Looking at the structure definition is enough to infer the serialization.
Data is serialized in the order listed in the FC_REFLECT macro
Strings & Arrays are prefixed with a variable length int that uses the same encoding as google protocol buffers.
In binary terms the data is simply copied with the same byte order as the host.. ie: it will not work on big endian systems.
Check out FC_REFLECT and fc/io/raw.hpp which defines the "raw binary" serialization based upon reflection.