diff --git a/Sources/EventSource/Data+Split.swift b/Sources/EventSource/Data+Split.swift
new file mode 100644
index 0000000..d06e376
--- /dev/null
+++ b/Sources/EventSource/Data+Split.swift
@@ -0,0 +1,47 @@
+//
+//  Data+Split.swift
+//  EventSource
+//
+//  Created by JadianZheng on 2025/7/24.
+//
+
+import Foundation
+
+extension Data {
+    func split(separators: [[UInt8]]) -> (completeData: [Data], remainingData: Data) {
+        var currentIndex = startIndex
+        var messages = [Data]()
+        
+        while currentIndex < endIndex {
+            var foundSeparator: [UInt8]? = nil
+            var foundRange: Range<Data.Index>? = nil
+            
+            let remainingData = self[currentIndex..<endIndex]
+            
+            for separator in separators {
+                if let range = remainingData.firstRange(of: separator) {
+                    
+                    if foundRange == nil || range.lowerBound < foundRange!.lowerBound {
+                        foundSeparator = separator
+                        foundRange = range
+                    }
+                }
+            }
+            
+            if let separator = foundSeparator, let range = foundRange {
+                let messageData = self[currentIndex..<range.lowerBound]
+                
+                if !messageData.isEmpty {
+                    messages.append(Data(messageData))
+                }
+                
+                currentIndex = range.upperBound
+            } else {
+                break
+            }
+        }
+        
+        let remainingData = currentIndex < endIndex ? self[currentIndex..<endIndex] : Data()
+        return (messages, Data(remainingData))
+    }
+}
diff --git a/Sources/EventSource/EventParser.swift b/Sources/EventSource/EventParser.swift
index 05aa31c..fe63323 100644
--- a/Sources/EventSource/EventParser.swift
+++ b/Sources/EventSource/EventParser.swift
@@ -21,12 +21,10 @@ struct ServerEventParser: EventParser {
         self.mode = mode
     }
 
-    static let lf: UInt8 = 0x0A
-    static let cr: UInt8 = 0x0D
-    static let colon: UInt8 = 0x3A
 
     mutating func parse(_ data: Data) -> [EVEvent] {
-        let (separatedMessages, remainingData) = splitBuffer(for: buffer + data)
+        let (separatedMessages, remainingData) = (buffer + data).split(separators: doubleSeparators)
+        
         buffer = remainingData
         return parseBuffer(for: separatedMessages)
     }
@@ -37,83 +35,4 @@ struct ServerEventParser: EventParser {
 
         return messages
     }
-
-    private func splitBuffer(for data: Data) -> (completeData: [Data], remainingData: Data) {
-        let separators: [[UInt8]] = [[Self.lf, Self.lf], [Self.cr, Self.lf, Self.cr, Self.lf]]
-        
-        // find last range of our separator, most likely to be fast enough
-        let (chosenSeparator, lastSeparatorRange) = findLastSeparator(in: data, separators: separators)
-        guard let separator = chosenSeparator, let lastSeparator = lastSeparatorRange else {
-            return ([], data)
-        }
-        
-        // chop everything before the last separator, going forward, O(n) complexity
-        let bufferRange = data.startIndex ..< lastSeparator.upperBound
-        let remainingRange = lastSeparator.upperBound ..< data.endIndex
-        let rawMessages: [Data] = if #available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, visionOS 1.0, *) {
-            data[bufferRange].split(separator: separator)
-        } else {
-            data[bufferRange].split(by: separator)
-        }
-        
-        // now clean up the messages and return
-        let cleanedMessages = rawMessages.map { cleanMessageData($0) }
-        return (cleanedMessages, data[remainingRange])
-    }
-
-    private func findLastSeparator(in data: Data, separators: [[UInt8]]) -> ([UInt8]?, Range<Data.Index>?) {
-        var chosenSeparator: [UInt8]?
-        var lastSeparatorRange: Range<Data.Index>?
-        for separator in separators {
-            if let range = data.lastRange(of: separator) {
-                if lastSeparatorRange == nil || range.upperBound > lastSeparatorRange!.upperBound {
-                    chosenSeparator = separator
-                    lastSeparatorRange = range
-                }
-            }
-        }
-        return (chosenSeparator, lastSeparatorRange)
-    }
-
-    private func cleanMessageData(_ messageData: Data) -> Data {
-        var cleanData = messageData
-
-        // remove trailing CR/LF characters from the end
-        while !cleanData.isEmpty, cleanData.last == Self.cr || cleanData.last == Self.lf {
-            cleanData = cleanData.dropLast()
-        }
-
-        // also clean internal lines within each message to remove trailing \r
-        let cleanedLines = cleanData.split(separator: Self.lf)
-            .map { line in line.trimming(while: { $0 == Self.cr }) }
-            .joined(separator: [Self.lf])
-
-        return Data(cleanedLines)
-    }
-}
-
-fileprivate extension Data {
-    @available(macOS, deprecated: 13.0, obsoleted: 13.0, message: "This method is not recommended on macOS 13.0+")
-    @available(iOS, deprecated: 16.0, obsoleted: 16.0, message: "This method is not recommended on iOS 16.0+")
-    @available(watchOS, deprecated: 9.0, obsoleted: 9.0, message: "This method is not recommended on watchOS 9.0+")
-    @available(tvOS, deprecated: 16.0, obsoleted: 16.0, message: "This method is not recommended on tvOS 16.0+")
-    @available(visionOS, deprecated: 1.0, obsoleted: 1.1, message: "This method is not recommended on visionOS 1.0+")
-    func split(by separator: [UInt8]) -> [Data] {
-        var chunks: [Data] = []
-        var pos = startIndex
-        // Find next occurrence of separator after current position
-        while let r = self[pos...].range(of: Data(separator)) {
-            // Append if non-empty
-            if r.lowerBound > pos {
-                chunks.append(self[pos..<r.lowerBound])
-            }
-            // Update current position
-            pos = r.upperBound
-        }
-        // Append final chunk, if non-empty
-        if pos < endIndex {
-            chunks.append(self[pos..<endIndex])
-        }
-        return chunks
-    }
 }
diff --git a/Sources/EventSource/EventSourceABNF.swift b/Sources/EventSource/EventSourceABNF.swift
new file mode 100644
index 0000000..f72a2bb
--- /dev/null
+++ b/Sources/EventSource/EventSourceABNF.swift
@@ -0,0 +1,50 @@
+//
+//  EventSourceEOL.swift
+//  EventSource
+//
+//  Created by JadianZheng on 2025/7/24.
+//
+
+import Foundation
+
+/*
+ * https://html.spec.whatwg.org/multipage/server-sent-events.html#server-sent-events
+ *
+ * Event Stream Format (ABNF):
+ * stream        = [ bom ] *event
+ * event         = *( comment / field ) end-of-line
+ * comment       = colon *any-char end-of-line
+ * field         = 1*name-char [ colon [ space ] *any-char ] end-of-line
+ * end-of-line   = ( cr lf / cr / lf )
+ *
+ * ; characters
+ * lf            = %x000A ; U+000A LINE FEED (LF)
+ * cr            = %x000D ; U+000D CARRIAGE RETURN (CR)
+ * space         = %x0020 ; U+0020 SPACE
+ * colon         = %x003A ; U+003A COLON (:)
+ * bom           = %xFEFF ; U+FEFF BYTE ORDER MARK
+ * name-char     = %x0000-0009 / %x000B-000C / %x000E-0039 / %x003B-10FFFF
+ *                 ; a scalar value other than U+000A LINE FEED (LF), U+000D CARRIAGE RETURN (CR), or U+003A COLON (:)
+ * any-char      = %x0000-0009 / %x000B-000C / %x000E-10FFFF
+ *                 ; a scalar value other than U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR)
+ */
+
+let lf: UInt8 = 0x0A    // \n
+let cr: UInt8 = 0x0D    // \r
+let colon: UInt8 = 0x3A // :
+
+let singleSeparators: [[UInt8]] = [
+    [cr, lf],   // \r\n
+    [cr],       // \r
+    [lf]        // \n
+].sorted { $0.count > $1.count }
+
+let doubleSeparators: [[UInt8]] = [
+    [cr, lf, cr, lf],   // \r\n\r\n
+    [lf, cr, lf],       // \n\r\n
+    [cr, cr, lf],       // \r\r\n
+    [cr, lf, lf],       // \r\n\n
+    [cr, lf, cr],       // \r\n\r
+    [cr, cr],           // \r\r
+    [lf, lf]            // \n\n
+].sorted { $0.count > $1.count }
diff --git a/Sources/EventSource/ServerEvent.swift b/Sources/EventSource/ServerEvent.swift
index 51e4893..d60783f 100644
--- a/Sources/EventSource/ServerEvent.swift
+++ b/Sources/EventSource/ServerEvent.swift
@@ -68,22 +68,28 @@ public struct ServerEvent: EVEvent {
     }
     
     public static func parse(from data: Data, mode: EventSource.Mode = .default) -> ServerEvent? {
-        let rows: [Data] = switch mode {
-        case .default:
-            data.split(separator: ServerEventParser.lf) // Separate event fields
-        case .dataOnly:
-            [data] // Do not split data in data-only mode
-        }
+        let recivedStr = String(data: data, encoding: .utf8)
+        
+        let rows: [Data] = {
+            switch mode {
+            case .default:
+                let (separatedMessages, remainingData) = data.split(separators: singleSeparators)
+                return separatedMessages + [remainingData]
+                
+            case .dataOnly:
+                return [data] // Do not split data in data-only mode
+            }
+        }()
 
         var message = ServerEvent()
         
         for row in rows {
             // Skip the line if it is empty or it starts with a colon character
-            if row.isEmpty || row.first == ServerEventParser.colon {
+            if row.isEmpty || row.first == colon {
                 continue
             }
             
-            let keyValue = row.split(separator: ServerEventParser.colon, maxSplits: 1)
+            let keyValue = row.split(separator: colon, maxSplits: 1)
             let key = keyValue[0].utf8String
 
             // If value starts with a SPACE character, remove it from value
@@ -111,7 +117,7 @@ public struct ServerEvent: EVEvent {
                 // If the line is not empty but does not contain a colon character
                 // add it to the other fields using the whole line as the field name,
                 // and the empty string as the field value.
-                if row.contains(ServerEventParser.colon) == false {
+                if row.contains(colon) == false {
                     let string = row.utf8String
                     if var other = message.other {
                         other[string] = ""
diff --git a/Tests/EventSourceTests/EventParserTests.swift b/Tests/EventSourceTests/EventParserTests.swift
index e737c38..59e2143 100644
--- a/Tests/EventSourceTests/EventParserTests.swift
+++ b/Tests/EventSourceTests/EventParserTests.swift
@@ -189,7 +189,7 @@ struct EventParserTests {
 
         // Test with mixed LF (\n) and CR+LF (\r\n) - using separate events
         let textMixed = "data: test mixedline1\n\n" +
-                       "data: mixedline2\r\n\n" +
+                       "data: mixedline2\n\r\n" +
                        "event: update\r\ndata: mixedtest\n\n" +
                        "id: 4\nevent: pong\r\ndata: mixedpong\r\n\n"