@author Craig Everett <craigeverett@qpq.swiss> [https://git.qpq.swiss/QPQ-AG/hakuzaru]
@version 0.8.2
@title Hakuzaru: Gajumaru blockchain bindings for Erlang

@doc
This Erlang application provides bindings for the Gajumaru blockchain and basic utilities for manipulating Gajumaru-related data.

== To Start or Not To Start ==
Starting the `hakuzaru' application is only required if you need to query the chain.

The application can be started via a call to `application', or with an explicit call to `hz:start()'.

Hakuzaru can also be run as a local application from the shell by invoking it with `zxh run hakuzaru' if you have `zx' installed.

== Operation ==
All blockchain-specific operations are accessible from the main interface modulle: `hz'

When Hakuzaru is started as an application a named process called `hz_man' is spawned that manages interactions with chain nodes, as well as a simple-one-for-one supervisor that manages the lifecycle of workers (defined in `hz_fetcher').

After startup `hz_man' must be given the address and port of a list of Gajumaru nodes that are available to service requests.
Note that the service nodes will need to have the dry-run endpoint enabled and the internal service query port made available in order to provide dry-runs and transaction submission.

When configuring chain nodes a list of nodes should be provided.
To avoid sync issues in the case of fast transaction formation/submission to the chain, only one node from the list of chain nodes is used for submitting transactions and querying `next_nonce/1`.
This node is called "the sticky node".

The first node in the list of chain nodes provided during configuration is designated as the sticky node.
If you also want to use the sticky node as a query endpoint, include it twice in the list.

The `hz_man' will round-robin requests to however many additional Gajumaru nodes are provided in the configuration.
Note that this configuration is dynamic and can be changed at runtime, so your service can adapt to node availability on the fly if needed.

```
ceverett@steak:~$ zxh run hakuzaru
Erlang/OTP 27 [erts-15.2] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1] [jit:ns]

Eshell V15.2 (press Ctrl+G to abort, type help(). for help)
Fetching otpr-hakuzaru-0.8.2
[100.00%]
Recompile: src/hz_sup
Recompile: src/hz_man
Recompile: src/hz_key_master
Recompile: src/hz_grids
Recompile: src/hz_format
Recompile: src/hz_fetcher
Recompile: src/hz
Recompile: src/hakuzaru
Starting otpr-hakuzaru-0.8.2.
hz_man starting.
Started [hakuzaru]
1> hz:chain_nodes([{"groot.testnet.gajumaru.io", 3013}]).
ok
2> hz:status().
{ok,#{"difficulty" => 2877405482,
      "finalized" =>
          #{"hash" =>
                "kh_PDSn6Xru5JVdpJfdDCNpfsL8gUZvvjyhTYuzgndoy98G5oLLR",
            "height" => 277454,"type" => "height"},
      "genesis_key_block_hash" =>
          "kh_Qdi5MTuuhJm7xzn5JUAbYG12cX3qoLMnXrBxPGzBkMWJ4K8vq",
      "hashrate" => 864394,"listening" => true,
      "network_id" => "groot.testnet",
      "node_revision" =>
          "7b3cc1db3bb36053023167b86f7d6f2d5dcbd01d",
      "node_version" => "0.1.0+203.7b3cc1db3",
      "peer_connections" => #{"inbound" => 1,"outbound" => 3},
      "peer_count" => 5,
      "peer_pubkey" =>
          "pp_2nQHucGyEt5wkYruNuRkg19cbZuEeyR9BZfvtv49F3AoyNSYMT",
      "pending_transactions_count" => 0,
      "protocols" =>
          [#{"effective_at_height" => 0,"version" => 1}],
      "solutions" => 0,"sync_progress" => 100.0,
      "syncing" => false,"top_block_height" => 277555,
      "top_hash" =>
          "kh_2vuNc8eG77aTmHcQDcievjKufFwR4MSSuZbEMWwW5TqUzSQy71",
      "top_key_block_hash" =>
          "kh_2vuNc8eG77aTmHcQDcievjKufFwR4MSSuZbEMWwW5TqUzSQy71"}}
'''