Async implementation of chained block streaming and parsing

In this example the block wire protocol is composed of a header and payload. Parts of a header are not represented in a serialized block because they are only relevant during the transport.

• First byte in a header represents the version of a protocol. Ideally first 4 bits could be reserved for future uses and remaining 4 bits could be used for message type if the communication flow would require it.
• Following 4 bytes indicates the lenght of the remaining data (payload).
• Next 32 bytes are for parent hash and other 8 bytes are for block number.
• Everything remaining are the contents of the block.