class Acme::Client::HTTPClient::ErrorMiddleware

Exceptions are rescued and re-packaged as Acme exceptions.
ErrorMiddleware ensures the HTTP Client would not raise exceptions outside the Acme namespace.

def call(env)

Implements the Rack-alike Faraday::Middleware interface. 
def call(env)
  @app.call(env)
rescue Faraday::TimeoutError, Faraday::ConnectionFailed
  raise Acme::Client::Error::Timeout
end