current_transaction always returns nil

[sivagollapalli]

require 'elastic_apm'
require 'pry'
require 'pry-nav'

app = lambda do |env|
  [200, {'Content-Type' => 'text/plain'}, ['ok']]
end

# Wraps all requests in transactions and reports exceptions
use ElasticAPM::Middleware

# Start an instance of the Agent
ElasticAPM.start(service_name: 'NothingButRack')

ElasticAPM.with_transaction do |tra|
  p tra.trace_id
end

run app

# Gracefully stop the agent when process exits.
# Makes sure any pending transactions are sent.
at_exit { ElasticAPM.stop }

ElasticAPM.running? returns true. But for some reason current_transaction always returns nil even if I call start_transaction explicitly.

[sivagollapalli]

for some reason when I set ELASTIC_APM_RECORDING to true it it working. But as per documentation https://www.elastic.co/docs/reference/apm/agents/ruby/configuration#config-recording true is the default value.