copy static method
creates a copy of the object (classmethod)
Implementation
static BtcTransaction copy(BtcTransaction tx) {
return BtcTransaction(
hasSegwit: tx.hasSegwit,
inputs: tx.inputs.map((e) => e.copy()).toList(),
outputs: tx.outputs.map((e) => e.copy()).toList(),
w: tx.witnesses.map((e) => e.copy()).toList(),
lock: tx.locktime,
v: tx.version);
}