fix: add parentheses to is_a? call in SSEClient#close

[dan98765]

What did you accomplish?

Fixed a TypeError: class or module required in SSEClient#close (line 50 of lib/splitclient-rb/sse/event_source/client.rb).

Without explicit parentheses, Ruby parses:

if @socket.is_a? OpenSSL::SSL::SSLSocket && @config.debug_enabled

as:

if @socket.is_a?(OpenSSL::SSL::SSLSocket && @config.debug_enabled)

Since OpenSSL::SSL::SSLSocket is truthy, && evaluates and returns the right operand (@config.debug_enabled, a boolean). Then is_a?(true) or is_a?(false) raises TypeError.

The rescue StandardError block catches it so it doesn't crash, but it fires on every SSE socket close and produces error-level log entries.

The fix adds explicit parentheses: @socket.is_a?(OpenSSL::SSL::SSLSocket).

Note that line 48 has a similar is_a? call without &&, so it parses correctly and doesn't need a change.

Fixes #623.

How to test new changes?

The fix is a Ruby parsing issue, not a logic change. You can verify the parsing difference in an IRB session:

obj = OpenSSL::SSL::SSLSocket
debug = true

# Without parens (current code) — TypeError
obj.is_a? OpenSSL::SSL::SSLSocket && debug
# => TypeError: class or module required

# With parens (this fix) — works correctly
obj.is_a?(OpenSSL::SSL::SSLSocket) && debug
# => true

Extra Notes

This was introduced in 8.11.0 when the && @config.debug_enabled guard was added to the is_a? check.