feat: rpc client support middleware

[gxcsoccer]

const client = new RpcClient({ ... });

client.use(async function(ctx, next) {
  try {
    await next();
  } catch (err) {
    assert(err.name === 'RpcNoProviderError');
    ctx.body = 'empty';
  }
});

const consumer = client.createConsumer({
  interfaceName: 'com.alipay.sofa.rpc.test.ProtoService',
  targetAppName: 'pb',
});
await consumer.ready();

const result = await consumer.invoke('echoObj', [{
  name: 'Peter',
  group: 'A',
}]);
assert(result === 'empty');

[codecov[bot]]

Codecov Report

Merging #36 into master will increase coverage by 0.01%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #36      +/-   ##
==========================================
+ Coverage   98.63%   98.65%   +0.01%     
==========================================
  Files          38       38              
  Lines        1837     1859      +22     
==========================================
+ Hits         1812     1834      +22     
  Misses         25       25

Impacted Files	Coverage Δ
lib/client/consumer.js	100% <100%> (ø)	:arrow_up:
lib/client/client.js	100% <100%> (ø)	:arrow_up:

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[gxcsoccer]

1.9.0