// Package chaincfg defines chain configuration parameters. In addition to the main Bitcoin network, which is intended
// for the transfer of monetary value, there also exists two currently active standard networks: regression test and
// testnet (version 3). These networks are incompatible with each other (each sharing a different genesis block) and
// software should handle errors where input intended for one network is used on an application instance running on a
// different network.
//
// For library packages, chaincfg provides the ability to lookup chain parameters and encoding magics when passed a
// *Params. Older APIs not updated to the new convention of passing a *Params may lookup the parameters for a
// wire.BitcoinNet using ParamsForNet, but be aware that this usage is deprecated and will be removed from chaincfg in
// the future.
//
// For main packages, a (typically global) var may be assigned the address of one of the standard Param vars
// for use as the application's "active" network. When a network parameter is needed, it may then be looked up through
// this variable (either directly, or hidden in a library call).
//
//  package main
//  import (
//          "flag"
//          "fmt"
//          "github.com/p9c/p9/pkg/util"
//          "github.com/p9c/p9/pkg/chain/config"
//  )
//  var testnet = flag.Bool("testnet", false, "operate on the testnet Bitcoin network")
//  // By default (without -testnet), use mainnet.
//  var chainParams = &chaincfg.MainNetParams
//  func main() {
//          flag.Parse()
//          // Modify active network parameters if operating on testnet.
//          if *testnet {
//                  chainParams = &chaincfg.TestNet3Params
//          }
//          // later...
//          // Create and print new payment address, specific to the active network.
//          pubKeyHash := make([]byte, 20)
//          addr, e := util.NewAddressPubKeyHash(pubKeyHash, chainParams)
//          if e != nil  {
//                  Log.Fatal <- err.Error()
//          }
//          fmt.Println(addr)
//  }
//
// If an application does not use one of the three standard Bitcoin networks, a new Params struct may be created which
// defines the parameters for the non-standard network. As a general rule of thumb, all network parameters should be
// unique to the network, but parameter collisions can still occur (unfortunately, this is the case with regtest and
// testnet3 sharing magics).
package chaincfg