refactor: make optional BlockId params required in provider functions

[EmperorOrokuSaki]

Motivation

This issue #514

Solution

Make the BlockId optional and use the default value if it's None.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[mattsse]

the tag is a required argument,

I think the option does not improve the API, because None is equal to Default::default() or BlockId::latest()

[EmperorOrokuSaki]

the tag is a required argument,

I think the option does not improve the API, because None is equal to Default::default() or BlockId::latest()

That is true, it is a required parameter in the RPC specification, but the other examples provided in the original issue have the same condition so it's a case of inconsistency a bit. I checked those methods and for those it's also required in the specification.

[mattsse]

I see, then we should change all Option<BlockId> to BlockId

[EmperorOrokuSaki]

I see, then we should change all Option<BlockId> to BlockId
Sounds good. I'll change them in this pr.

[EmperorOrokuSaki]

In some files previously None was supplied when the arg was of the type Option<BlockId>, I changed those to BlockId::default() since that was the final value.

[prestwich]

I think the option does not improve the API, because None is equal to Default::default() or BlockId::latest()

The only improvement is writing None is fewer characters than Default::default(). Seems kinda pointless. in favor of this change

[prestwich]

alternate API designs would be to bifurcate, which seems ok-but-verbose on our end

fn call_with_block(..., block_id: BlockId)
fn call(...) { self.call_with_block(..., Default::default()) }

or to switch to a rpc builder pattern for return values of those types. which seems bad