private PSBT(Transaction transaction, Network network)
 {
     if (transaction == null)
     {
         throw new ArgumentNullException(nameof(transaction));
     }
     Network = network;
     tx      = transaction.Clone();
     Inputs  = new PSBTInputList();
     Outputs = new PSBTOutputList();
     for (var i = 0; i < tx.Inputs.Count; i++)
     {
         this.Inputs.Add(new PSBTInput(this, (uint)i, tx.Inputs[i]));
     }
     for (var i = 0; i < tx.Outputs.Count; i++)
     {
         this.Outputs.Add(new PSBTOutput(this, (uint)i, tx.Outputs[i]));
     }
     foreach (var input in tx.Inputs)
     {
         input.ScriptSig = Script.Empty;
         input.WitScript = WitScript.Empty;
     }
 }
        internal PSBT(BitcoinStream stream, Network network)
        {
            Network = network;
            Inputs  = new PSBTInputList();
            Outputs = new PSBTOutputList();
            var magicBytes = stream.Inner.ReadBytes(PSBT_MAGIC_BYTES.Length);

            if (!magicBytes.SequenceEqual(PSBT_MAGIC_BYTES))
            {
                throw new FormatException("Invalid PSBT magic bytes");
            }

            // It will be reassigned in `ReadWriteAsVarString` so no worry to assign 0 length array here.
            byte[] k       = new byte[0];
            byte[] v       = new byte[0];
            var    txFound = false;

            stream.ReadWriteAsVarString(ref k);
            while (k.Length != 0)
            {
                switch (k[0])
                {
                case PSBTConstants.PSBT_GLOBAL_UNSIGNED_TX:
                    if (k.Length != 1)
                    {
                        throw new FormatException("Invalid PSBT. Contains illegal value in key global tx");
                    }
                    if (tx != null)
                    {
                        throw new FormatException("Duplicate Key, unsigned tx already provided");
                    }
                    tx = stream.ConsensusFactory.CreateTransaction();
                    uint size = 0;
                    stream.ReadWriteAsVarInt(ref size);
                    var pos = stream.Counter.ReadenBytes;
                    tx.ReadWrite(stream);
                    if (stream.Counter.ReadenBytes - pos != size)
                    {
                        throw new FormatException("Malformed global tx. Unexpected size.");
                    }
                    if (tx.Inputs.Any(txin => txin.ScriptSig != Script.Empty || txin.WitScript != WitScript.Empty))
                    {
                        throw new FormatException("Malformed global tx. It should not contain any scriptsig or witness by itself");
                    }
                    txFound = true;
                    break;

                case PSBTConstants.PSBT_GLOBAL_XPUB when XPubVersionBytes != null:
                    if (k.Length != 1 + XPubVersionBytes.Length + 74)
                    {
                        throw new FormatException("Malformed global xpub.");
                    }
                    for (int ii = 0; ii < XPubVersionBytes.Length; ii++)
                    {
                        if (k[1 + ii] != XPubVersionBytes[ii])
                        {
                            throw new FormatException("Malformed global xpub.");
                        }
                    }
                    stream.ReadWriteAsVarString(ref v);
                    KeyPath path          = KeyPath.FromBytes(v.Skip(4).ToArray());
                    var     rootedKeyPath = new RootedKeyPath(new HDFingerprint(v.Take(4).ToArray()), path);
                    GlobalXPubs.Add(new ExtPubKey(k, 1 + XPubVersionBytes.Length, 74).GetWif(Network), rootedKeyPath);
                    break;

                default:
                    if (unknown.ContainsKey(k))
                    {
                        throw new FormatException("Invalid PSBTInput, duplicate key for unknown value");
                    }
                    stream.ReadWriteAsVarString(ref v);
                    unknown.Add(k, v);
                    break;
                }
                stream.ReadWriteAsVarString(ref k);
            }
            if (!txFound)
            {
                throw new FormatException("Invalid PSBT. No global TX");
            }

            int i = 0;

            while (stream.Inner.CanRead && i < tx.Inputs.Count)
            {
                var psbtin = new PSBTInput(stream, this, (uint)i, tx.Inputs[i]);
                Inputs.Add(psbtin);
                i++;
            }
            if (i != tx.Inputs.Count)
            {
                throw new FormatException("Invalid PSBT. Number of input does not match to the global tx");
            }

            i = 0;
            while (stream.Inner.CanRead && i < tx.Outputs.Count)
            {
                var psbtout = new PSBTOutput(stream, this, (uint)i, tx.Outputs[i]);
                Outputs.Add(psbtout);
                i++;
            }
            if (i != tx.Outputs.Count)
            {
                throw new FormatException("Invalid PSBT. Number of outputs does not match to the global tx");
            }
        }