Building the TransactionHeader
Transactions and their headers are built using Google Protocol Buffer, or Protobuf, format. This allows data to be serialized and deserialzed consistently and efficiently across multiple platforms and multiple languages. The Protobuf definition files are located in the /protos directory, at the root level of the sawtooth-core repo. These files will have to first be compiled into usable Protobuf classes. Then, serializing a TransactionHeader is just a matter of plugging the right data into the right keys.