Refactor Fluent Logger for Improved Thread Safety and Error Handling

[aaithal]

Summary

This PR refactors the Fluent logger implementation to improve certain aspects of thread safety and error handling.

Key Changes

1. Thread Safety

• Introduced thread-safe wrapper methods with sync prefix that handle their own locking
• Improved mutex usage patterns to prevent potential deadlocks
• Added proper double-checking of the closed flag after acquiring locks

2. Error Handling

• Added proper error handling for SetWriteDeadline() and SetReadDeadline()
• Implemented context cancellation checks throughout the codebase
• Used Go 1.13+ error wrapping with %w for better error context preservation
• Added more specific error messages with consistent prefixes

3. Connection Management

• Created syncClose() method to safely close connections
• Added syncConnectWithRetry() to handle connection establishment in a thread-safe manner
• Improved connection state checking to prevent operations on nil connections

4. Read Timeout Support

• Added support for read timeouts when reading acknowledgments
• Added a new ReadTimeout configuration option with appropriate defaults
• Set read deadlines on connections

5. Context Propagation

• Ensured context is properly propagated to all network operations
• Added context cancellation checks at critical points to allow early exit
• Improved handling of context cancellation in the run() goroutine

Testing

All existing tests pass with these changes. The refactoring maintains backward compatibility while improving the robustness of the code.